Hitchhiker on my snail...What is it?

[rhodan]

I have a snail that has this "growth" on it's shell....I know these pictures are not all that clear and I will try to get a better picture(s) later, but I'm curious if anyone can make it out and let me know what it is?
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[spike]

looks like sponges

 

[skriz]

Look like those crypto sponges...surprised they're surviving in the light!