The Self D-Struct Machine (ボウリングスピン Bouringusupin?, lit. "Bowling Spin"), or the D-Struct Machine for short, is a character that appears in the Sonic the Hedgehog series. It is a robot created by Dr. Robotnik, who used it during the first part of the Angel Island incident.
The Self D-Struct Machine is a green and gray-colored hovering robot. It has small lamps on the top and below, a metal electric bar with a spinning top attachment that functions as a floating platform with a set of spikes spinning on its border.
Sonic the Hedgehog 3 & Knuckles
In Sonic the Hedgehog 3, and its lock-on version Sonic the Hedgehog 3 & Knuckles, the Self D-Struct Machine was used by Dr. Robotnik in an effort to destroy Sonic the Hedgehog and Miles "Tails" Prower in Carnival Night Zone. The robot, however, was defeated by the heroes.
Some time later, a re-built Self D-Struct Machine was sent to destroy Knuckles the Echidna in Carnival Night Zone. However, the echidna managed to destroy the robot on his own.
The Self D-Struct Machine is the sub-boss of Carnival Night Zone in Sonic the Hedgehog 3 and Sonic the Hedgehog 3 & Knuckles, and the seventh boss overall in these games. In Sonic the Hedgehog 3, it is battled by Sonic and Tails, while in Sonic the Hedgehog 3 & Knuckles, it can also be battled with Knuckles.
The Self D-Struct Machine is encountered in an elevator room with a floor made of yellow and green blocks that descend down a vertical tunnel. After landing in the arena, the D-Struct Machine releases its twirling spike-covered top that will bounce around the room and destroy the yellow-and-green blocks on the floor upon contact with them. The rest of the mecha will hover from side to side constantly and will only stop when hit by the player. The spinning top also acts as a platform, while the player must avoid the bottom part and the spikes on the platform.
The player has limited time to defeat the D-Struct Machine, as the spinning top will eventually destroy the whole floor, leaving the player to fall to their death. To compensate for the limited time, the D-Struct Machine is weaker than the other mini-bosses in the game and only has to be struck four times rather than six to be destroyed. However, the player cannot damage the D-Struct Machine directly. After hitting the D-Struct Machine once, the tube on its bottom will extend and surround itself with an electric field that will hurt the player if they touch it. At this point, the player must let the spinning top bounce back into it.
After the D-Struct Machine has been defeated by hitting it four times, the arena floor will reach the bottom of the vertical tunnel and the Goal Plate will drop from the top of the screen. At this point, Sonic can fall down through any gaps that may have opened up in the floor at this point or be crushed by the rest of the blocks that are coming down due to the D-Struct Machine leaving uneven holes between the blocks.
Knuckles' battle against the D-Struct Machine is identical in Sonic the Hedgehog 3 & Knuckles. However, in this version, Knuckles enters to the elevator from his own pathway in the Zone. During the battle, Knuckles is unable to climb on the elevator room's walls and, depending how long the battle lasts, the player may need to use the D-Struct Machine's spinning top to reach the D-Struct Machine in order to hit it due Knuckles' low jumping height.
- The D-Struct Machine's ability to destroy the floor of the battle arena is heavily reminiscent of the Spring Yard Zone boss in the original Sonic the Hedgehog.
- Strangely, a Lightning Shield does not protect the character from hitting the electric field that forms around the tube on the bottom of the boss (the shield is lost as soon as such a hit is sustained).
- Spin Jumping up into the spinning top from below forces it upwards.
- After both versions of the battle, when the signpost falls to the bottom ground, hidden monitors (Super Ring, Water Shield and Lightning Shield) can be found in the center part of the ground.
- At the end of the battle, if the player remains ducking (while having the camera scrolled to the bottom), the signpost will fall below through the ground.