Sponge
Sponges are enemies found in the 
Flooded Caves that will orbit a set distance around Isaac, moving with him. It will swell in size 1 stage every 6 damage it takes and can swell multiple stages at a time if it takes 12 or 18 damage. Each stage causes it to become heavier and orbits more clumsily the larger they get.
It can can swell up to 3 times, and after after not taking damage for a period, it will deflate, releasing rings of spectral projectiles while doing so. The larger a Sponge is, the shorter amount of time it takes before it deflates, however, taking damage will cause the Sponge to delay deflating unless at max size.
The amount of projectiles it releases is based on the Sponge's current size. With the first stage firing 6 single projectiles, second stage releasing 6 streams of 3 projectiles each, and the final stage releasing 6 streams of 6 projectiles. In addition, the more projectiles it releases, the longer the attack lasts.
Trivia
- Sponge was originally from the unreleased Flooded Caves Overhaul MOD.
Gallery
Various stages of a Sponge's inflation.
