Dive Eggman

Dive Eggman is the mini-boss of Hydrocity Zone and the thirteenth overall boss of Sonic Mania. He is fought with Sonic, Tails or Knuckles at the end of Hydrocity Zone Act 1.

Boss guide
The boss battle "begins" with a short cutscene of Dr. Eggman wearing a scuba outfit deploying bombs that cause the water level to rise, initiating a short segment where the player must avoid being crushed in between the rising ground and the ceiling. After the segment, the player jumps into an Egg Mobile with the Waterspout and Depth Charge attachment.

During the next phase, Dr. Eggman will be swimming back and forth in a pool of water underneath the player. To attack Eggman, use the Egg Mobile's impeller to suck up him out of the water and into a water plume; once Eggman hits the impeller, he will take damage. To activate the impeller, the player must hold down any of the jump buttons. While in the water, Eggman will try to swim away, but once he is in the water plume, he will be helpless until the player disables the impeller.

To defend himself, Eggman will deploy floating bombs that are susceptible to getting sucked up by the player too and will damage them if they touch the Egg Mobile. The depth charges on the Egg Mobile, which can be deployed by pressing down on the directional controls, can also be used to destroy the bombs, but will bounce off Eggman himself.

After four hits, Eggman's scuba suit explodes and he falls off the screen in defeat. The player can then hover to the right to finish the Act.