The caterpillar for the Dasychira Pudibunda moth resembles a sponge. This caterpillar is yellow and from a distance looks like a very small sponge.
Sponge
sponge bob looks like a square because he is supposed to look like a dish washing, house hold sponge
A stone is a stone and stonefish is a poisonous fish that looks like a stone but if you step on it it injects poison into your foot.
Bone marrow.
pearl stone looks like a white stone...
Stonefish. The fish looks like a stone and looks rather brown
A larva is an immature form of a sponge looks very different from the adult sponge.
At times its Ms. Puff.
Pyrite
It looks like sponge but it's the calcium in your bone
I think your thinking of Mrs.Puff lol hahahha !