Any Ideas what this is?

The yellow thing in the center of the picture, Its about the size of a nickel at its base and looks like a sponge.

 

Pineapple sponge. It's harmless.

I have some that are elongated, some are shorts and squat.

 

Yes, you're correct that it's a sponge but it's not a pineapple sponge. Pineapple sponges come from the Scypha or Leucilla species.

 

Def a sponge, not sure what kind.

 

I have one like this that is yellow as well, I was told that it was a pineapple so I assumed this one was as well. I also have a bluish one like that.

Sorry for this mis-info then

 

From this; Google Image Result for http://www.junglewalk.com/animal-pictures/682/Yellow-Sponge-14643.jpg it is simply called a Yellow Sponge.

 

i got a HUGE spong just like that hes spread like 7 inches all around my rock