what is this growing inside of a snail's shell?

[jarviz]

uhhh... what is this? looks like sponge type thing, but i can definitely see the "mouth" or tentacles forming. that's just an empty shell so i can just throw it out.. but i want to let it grow and see what it actually is.

 

[vetteguy53081]

Looks like tube worms and im not surprised- They sure know how to find inconspicuous spots.
They are harmless and generally send out a fan to capture food.

 

[kenchilada]

Looks like tube worms and im not surprised- They sure know how to find inconspicuous spots.
They are harmless and generally send out a fan to capture food.

Think so? Kind of looked like a sponge to me.

 

[jarviz]

Looks like tube worms and im not surprised- They sure know how to find inconspicuous spots.
They are harmless and generally send out a fan to capture food.

don't tube worms usually have white calcified shells? these look clear and soft.

 

[mtfish]

Looks like a tunicate.

 

[jarviz]

Looks like a tunicate.

woah cool. i just googled it and this might be it. i've never even seen these before in a tank.