Hitchhiker clam??

[fallinapart]

I bought this rock about 3 weeks ago, I picked this because of the shell looking thing attached to it, thinking it was just part of the rock. It has been in my tank looking like a rock since then, at least, until today when it was opening and closing as per the pictures below.

Is this a type of clam or what, it is prementaly attached to the rock, I tried to gently remove it, after seeing it open, but it is firmly attached. Any infor would be appreciated

I sure hope the pictures make it. 1st attempt to upload pics in message here.

 

[Mushroomman]

looks like some kind of bivalve to me, sometimes they make it some times they perish, do you know if its dead or alive? Either way it would be fine to leave it in there.

 

[fallinapart]

looks like some kind of bivalve to me, sometimes they make it some times they perish, do you know if its dead or alive? Either way it would be fine to leave it in there.

It is alive, as it will open up and close several times, espically when a snail is on it. It was just a big surprise to see it moving when I thought it was just rock Gave me a whole new meaning to live rock*twirlysmi

 

[CoolWaters]

Gave me a whole new meaning to live rock*twirlysmi

lol i would be freaked out

theres a small clam in my LR too. but it seems to be thousands of years old. so if its alive....

too bad its not a maxima clam...