Item Boxes that contain Special Combination display a black icon of Sonic and Tails' right hands holding firmly onto each other on their screen. Also, unlike in other cases with power-ups, the Item Boxes containing Special Combination are golden.
In gameplay, Special Combination is a rare Item Box power-up that only appears in Oil Desert Zone and Sky Fortress Zone. When picking up this Item Box's power-up, the screen will turn dark and Sonic and Tails (with the latter accompanying the former during a playthrough) will start bouncing around on the screen while using the Spin Attack, destroying any Badnik they collide with. During this, a button prompt will appear on the screen that instructs the player to press / for five seconds to increase the Ring and point value of the attack. At the end of this combo attack, Sonic and Tails will come back together for a unified slam into the ground that destroys any remaining Badniks. Afterward, the player will be rewarded with a certain amount of Rings and points.