Sponge or worm on my torch??

[Bartanto]

Any ideas on this thing? I’m leaning sponge as the structure this dude resides on is on has a sponge network - but it sure is really round, and this touch is not looking great AT all. Major flesh band recession and much less extension lately and ventricles are much flatter and frail looking on this head.

 

[GoReefin]

Sponge