Iron ball

The iron ball (鉄球), also known as the spike ball (トゲボール) or spiked ball, is an obstacle that appears in the Sonic the Hedgehog series. It is a variant of the more common Spikes, being a metal sphere covered in harmful spikes.

Description
Iron balls have maintained an overall consistent design over the course of the Sonic series, being heavy gray/black spheres that are covered in white/gray spikes. The dimensions of the iron balls tends to vary from game to game though.

In gameplay, when a playable character physically touches a iron ball, they will receive damage. As such, they usually serve as obstacles that are placed along the player's way in the levels. Occasionally, the iron balls will be stationary. In different games however, they tend to be attached to chains or other devices that causes them to swing around. On other occasions, the iron balls will be moving around in midair on their own.

In later games such as Sonic Unleashed, Sonic and the Black Knight and Sonic Generations, spike balls are usually set just on, or embedded in the ground.

Sonic the Hedgehog (16-bit)
The iron balls made their first appearance in the 16-bit version of Sonic the Hedgehog. In this game, they appear in various forms and sizes.

Spring Yard Zone features both large gray iron balls that float around in various patterns, and smaller darker rows of iron balls that spin around fixed points inside narrow passageways. Medium-sized gray iron balls with chains attached to them also circle around fixed points in Labyrinth Zone and Scrap Brain Zone Act 3. Star Light Zone also has Seesaws that use small iron balls as counterweights. Lastly, there is Scrap Brain Zone Act 2 which has large gray iron balls attached to chains that swing back and forth.

Sonic the Hedgehog (8-bit)
In the 8-bit version of Sonic the Hedgehog, the iron balls make a brief appearance in Labyrinth Zone. Here, small gray iron balls orbit blue orbs that are embedded in the Walls.

Sonic the Hedgehog 2 (16-bit)
In Sonic the Hedgehog 2, small and black slow-moving iron balls with gray spikes and green chains attached to them can be found orbiting platforms in Mystic Cave Zone.

Sonic the Hedgehog CD
In Sonic the Hedgehog CD, the iron balls make a few appearances. In Wacky Workbench, there are strings of small gray iron balls that rotate around a fixed point. Also, in Stardust Speedway, there are bluish iron balls with long gray spikes. These iron balls float left and right on surfaces or move up and down through small devices that either float in midair or sit embedded in the ground.

Sonic the Hedgehog 3 & Knuckles
In Sonic the Hedgehog 3, Sonic & Knuckles and its lock-on continuation Sonic the Hedgehog 3 & Knuckles, there are specific iron balls that block the player's path using different methods.

In Marble Garden Zone, there are large gray iron balls attached to poles via chains. These iron balls swing around their poles either horizontally or vertically (depending on whether their poles are attached to a vertical or horizontal surface). Also, in Launch Base Zone Act 1, the player will encounter the Swing’m Spikez, a sub-boss that attacks by swinging around chains with small iron balls at their ends.

In Mushroom Hill Zone, rows of black iron balls with gray spikes appear during the boss battle with the Jet Mobile. Curiously, these iron balls will flash when the Jet Mobile takes damage. Also, in Flying Battery Zone, there are more high-tech-looking iron balls. In the outdoor sections of Flying Battery Zone, these iron balls orbit fixed points, and in the indoor sections, they sit by themselves, moving up and down in accordance to the magnetic currents running through the ceiling above them. In addition, the sub-boss Gapsule in Flying battery Zone uses iron balls from Marble Garden Zone at the end of its arms to attack the player.

Lava Reef Zone features a large variety of different iron balls. In both Acts, there are small gray iron balls with chains attached to them that circle around fixed points. Also, exclusive to Lava Reef Zone Act 1 are iron balls identical to those from Marble Garden Zone that roll back and forth on the ground on their own. Exclusive to Act 2 on the other hand are medium-sized gray iron balls that circle around walkable or passable cylinders, or around plaforms. Lastly, while fighting the Hot Mobile in Lava Reef Zone Act 2, the boss will deploy black iron balls and with gray spikes. In order to damage the Hot Mobile, the player has to let the iron balls collide with the Hot Mobile. Like the iron balls during the Jet Mobile fight, these iron balls flash when the Hot Mobile takes damage.

In Sonic the Hedgehog 3 & Knuckles, iron balls also appear during Knuckles' edition of the Jet Drill battle. During this battle, the Jet Drill will fire a chain of iron balls from one of four different locations (either from the ceiling or from the floor) which will then re-emerge from another location. The Jet Drill itself will then travel along this chain before repeating the process. The formation of the iron ball chain is different each time.

Knuckles' Chaotix
In Knuckles' Chaotix, the iron ball are known as the spike ball (トゲボール). In this game, black iron balls with gray spikes appear only in the Special Stages, where they lie along the player's path. Some of the Bumpers also have iron balls connected to them by chains that sweeps the area around them.

Touching an iron ball in the Special Stage will make the player lose ten Rings.

Sonic 3D Blast
In Sonic 3D Blast, the iron balls made various appearances. In Green Grove Zone, there are iron balls with purple details that float around on their own in various patterns. The Zone also features Hunter Badniks that have iron balls orbiting their bodies. Also, during the encounter with the Green Grove Zone boss, Eggman will be equipped with a large gray iron ball that he will attempt to drop on Sonic. This iron ball bounces a few times when dropped.

Rusty Ruin Zone features iron balls which appear to be made of stone. Among them are large ones that swing around poles that they are attached to via chains, and unique ones that appear like statues built into the ground.

Sonic Adventure
In Sonic Adventure and Sonic Adventure DX: Director's Cut, iron balls became slightly more common obstacles. In these games, they are rather large and dark gray with slightly lighter spikes and polished surfaces.

Some iron balls have chains attached to them and swing around a fixed point (which sometimes goes up and down). Other pairs of iron balls have poles attached between them and spin together around a shared fixed point. There are also some iron balls that simply float in midair, and some of them will be periodically slamming into the ground. Additionally, some iron balls are arranged so that they move around in rows.

Sonic Adventure 2
In Sonic Adventure 2 and its remake Sonic Adventure 2: Battle appear again as obstacles. In these gams, they are black with red-purple spikes on then.

Much like in Sonic Adventure and Sonic Adventure DX: Director's Cut, they often come in pairs with poles attached between that spin around a fixed point together. In other cases, they are simply floating in midair or rolling along the ground.

Sonic Advance
In Sonic Advance, the typical iron ball is called the Iron Ball with Thorns (トゲ付き鉄球). In gameplay, gray iron balls with gray spikes appear in Angel Island Zone and yellow iron balls with gray spikes appear in Egg Rocket Zone. In both Zones, these iron balls float around in midair in different patterns.

During the battle with the Casino Paradise's boss, the Egg Ball, a technological-looking iron ball will appear from the same tubes that the Egg Ball is flying through as a distraction.

Sonic Advance 2
In Sonic Advance 2, the iron ball is referred to as the Iron Ball with Thorn (刺付き鉄球) again. In this game, the iron balls are teal-colored with gray spikes, and are only encountered in Egg Utopia. In gameplay, they float around in midair in different patterns.

Sonic Advance 3
In Sonic Advance 3, small gray iron balls appear in Route 99 and Chaos Angel where they serve as the Seesaw gimmicks' counterweights.

Sonic Heroes
In Sonic Heroes, the iron balls appear as fairly standard obstacles in the stage. In this game, they are large black balls with gray spikes.

In gameplay, the iron balls float in midair in stationary positions. They typically appear along tracks where the player has little time to avoid them, like along rails, on Bobsled courses, or during the flight segments in Bullet Station. also, the main artillery cannons on the Egg Albatross will be firing iron balls at the player.

Sonic the Hedgehog (2006)
In Sonic the Hedgehog (2006), the iron balls appear as both obstacles and objects to be used by the player. In this game, they are black with a multitude of gray spikes on them.

In gameplay, the surfaces on iron balls will deal out damage to playable characters, objects and enemies that touch them. Also, in Action Stages like Dusty Desert and Kingdom Valley, local loose iron balls will be rolling down inclines. In other cases, the iron balls will be partially embedded in the ground to serve as stationary obstacles. In addition, Silver can grab any free iron balls with his Psychokinesis and utilize them as projectiles.

Sonic and the Secret Rings
In Sonic and the Secret Rings, iron balls appear as common obstacles. In this game, they are large and gray with broad white spikes on them and golden frames around the bottom of said spikes.

In gameplay, the iron balls can be found in a multitude of places. Some are placed or embedded in the ground, others float on the surface of water sections, and others float in midair. Some iron balls also move around in certain patters, like left or right, up or down, and around paths. Also, at the end of Sand Oasis's second mission, some iron balls will get in the player's way by rolling down a hill.

Sonic and the Black Knight
In Sonic and the Black Knight, the iron balls made a return appearance. In this game, they are completely black with similarly dark spikes on them. They also come in different sizes, ranging from big to medium-sized.

In gameplay, the iron balls are half buried in the ground along the paths for the simple purpose of acting as road obstacles.

Sonic Rush Adventure
In Sonic Rush Adventure, iron balls are a rare obstacle. In this game, they are completely purple.

In gameplay, iron balls are only encountered during the 3D grinding segment at the end of Plant Kingdom Act 2. During this segment, iron ball will be situated on the Grind Rails, and it is the player's job to dodge them.

Sonic Unleashed
In both the Xbox 360/PlayStation 3 and Wii/PlayStation 2 version of Sonic Unleashed, the iron balls appear as obstacles. In this game, they look identical to how they appeared in Sonic the Hedgehog (2006).

In gameplay, iron balls are somewhat uncommon obstacles, as they only appear on rare occasions in regular stages. In the stages available through DLCs however, they are quite common. They typically appear in the daytime stages, and only make a few rare appearances in the nighttime stages.

Iron balls are commonly found floating in midair. Some of them float around in different patterns by themselves or together with others, while others float in fixed positions, sometimes in different formations. On a few rare occasions, they can also be found lying on the ground, often acting as blockades.

In the Wii/PlayStation 2 version of Sonic Unleashed, the iron balls have extra mechanics and usages. As seen in the daytime Acts of Eggmanland, some iron balls will be floating in the air, only to come down on the ground when the player approaches them. Also, in Act III: Beyond the Factory for the nighttime version of Eggmanland, there will be machines depositing iron balls over bottomless pit, thus creating temporary barriers that the player has to be careful about passing through.

Sonic the Hedgehog 4: Episode I
In Sonic the Hedgehog 4: Episode I, the iron balls make a brief appearance as obstacles. In this game, they are black with stubby gray spikes on them.

In gameplay, the iron balls appear during the chase segment of the boss battle with the Flying Eggman. Here, Dr. Eggman will occasionally throw iron balls down on the path in front of him for Sonic to collide with. Curiously, if Sonic does collide with an iron ball, the latter will disappear immediately after dealing damage.

Sonic Colors
In both the Wii and Nintendo DS version of Sonic Colors, the iron balls appear as obstacles. In the Wii version of the game, they look much like they did in Sonic the Hedgehog (2006). Meanwhile, on the Nintendo DS version, the iron balls are black with stubby white spikes.

In the Wii version of the game, the iron balls are recurring obstacles. On their own, they can be found floating in midair (or underwater). Some of them float around in certain patterns while others float in stationary positions. Whether they are moving or not though, the iron balls often appear in different iron ball formations. Some moving iron balls also have chains attached to them that keep them circling around a fixed point. Additionally, a few enemies and bosses make use of the iron balls. Certain Sprinklers will spit out iron balls to drop on the playable character, and the Frigate Orcan and Frigate Skullian will drop iron balls on the player's track.

In the Nintendo DS version of the game, the iron balls only appear during the boss battles with the Frigate Orcan and Frigate Skullian. Like on the Wii version, these bosses will periodically drop iron balls in hopes of hitting Sonic with them. After hitting the track once however, these iron balls will fall off of it.

Sonic Generations
In the console/PC version of Sonic Generations, the iron balls appear once more like obstacles. In this game, they look exactly like they did in the Wii version of Sonic Colors.

In gameplay, iron balls only make a few appearances in the main stages, namely in Speed Highway Act 1 and Seaside Hill Act 1. However, they make frequent appearances in the game's Challenge Acts. In terms of the layout concerning the iron balls, the iron balls may sometimes lie firmly on the ground. In most cases however, they float in midair. Some of these iron balls either sit still in midair while others move around in different patterns, sometimes by themselves or in formations with other iron balls. Some of them also circle around a fixed point that they have been chained to. Miniature iron balls also appear as counterweights on the Seesaws in the game.

Sonic Lost World
They reappear as standard obstacles in Sonic Lost World. They appear most frequently in auto running sections, either embedded in the ground as in Desert Ruins Zone 2, or simply floating and possibly even moving around the platforms.

Sonic Runners
Iron balls appear occasionally as obstacles in Sonic Runners. Dr. Eggman will also drop iron balls in the Iron Ball Eggmobile fight.

Sonic Runners Adventure
Iron balls play the same role in Sonic Runners Adventure as they do in it's predecessor, up to and including being dropped by Eggman in a boss fight.

Sonic Mania
In Sonic Mania, and its expansion Sonic Mania Plus, iron balls appear as regular obstacles, particularly in Flying Battery, Stardust Speedway, and Lava Reef. They appear both on their own (including the variants in Flying Battery that are periodically raised by the Zone's electromagnets) and swinging on chains. Some enemies, such as the Robot Bees and Heavy Rider, also wield iron balls attached to chains that they use as offensive weapons.

Sonic Forces
They reappear once again in Sonic Forces. They can be seen both floating (stationary or not) and swinging around on chains. During the first boss fight with Infinite, taking damage from his cubes can potentially lead to a virtual reality with iron balls to avoid. Their appearance is identical to their design in Sonic Lost World.