ID please

[CK Amstutz]

I have two of these and started off small. They both are getting huge and I don’t know what they are. A type of mushroom? Thank you!

 

[Llyod276]

If its not attached to anything flip it over, does it shrink to a touch, strong current? Does it have a foot? If you eat it, do you see strange things and hear noises? If yes then prolly is.