Amoeba Droid is the second mini boss encountered in Sonic Mania, encountered at the end of the Act 1 of Chemical Plant Zone. It is a spherical machine with three prominent prongs, not unlike the Big Icedus mini boss fought in Sonic the Hedgehog 3's IceCap Zone. It is encountered above a pool of a bubbling, damaging blue chemical which subsequently becomes a common hazard in Act 2.
The Amoeba Droid will initially dive into the chemical pool below and emerge coated in it, rendering it damaging to the touch, and will proceed to bounce towards the player several times. The coating then breaks, turning into small orbs orbiting the machine around the middle; the droid can now be safely attacked, but the orb's orbital inclination steadily changes, potentially hitting the player as they try to attack the robot from below. The orbs are then cast off, damaging any player they hit, and the machine sits in place for a split second before diving back into the toxic brew below it. This cycle repeats until the Amoeba Droid is dealt six hits, at which point it explodes and the act is completed.
If a Super character deals the final blow to the Amoeba Droid while it is still coated with chemicals, the player will revert to normal form and take damage immediately before the machine explodes.