Astrea Snail growing corals?

I bought this 10 Astrea Snails to get rid of my algae... but one of my snail has this weird stuff growing on his shell.. to me it looks like a coral or some kind of plant.. is this normal? should i be concerned (is it some sickness/tumor)? and what should i do..


http://i941.photobucket.com/albums/ad251/petmania/IMG_5447.jpg
http://i941.photobucket.com/albums/ad251/petmania/IMG_5445.jpg

 

Wow that's cool.. So what's gonna happen to the snail?
And what should I do if the snail dies? Let it be?

 

When the snail dies, if the coral is still alive, glue the shell somewhere and let it grow!

 

Free coral with snail purchase. Can't beat that.

 

Okay! Thank you lots!

 

Had an astrea with porites as well. Too bad it kept getting too close to my acans. RIP porites....

 

Awww thanks, NT. I can't take credit for it though. It was my better half. I can just look at a camera and break it for some reason. She won't let me even near her camera equipment

 

will pagoda cup grow like that? It looked like a baby pagoda with the polyps sticking out like that.