Strange Pod Showed Up in Aquarium

[ryangorney]

Can anyone tell me what this strange pod (second and third picture) is that suddenly showed up in my aquarium? I am not sure if I should remove it. I recently lost three fish after soemone else took care of my tank while I was out of town. Not sure what the cause but the pod and the white shell (first picture) suddenly appeared.

 

[Smitty]

It's kinda hard to tell, but they look like sponges to me.

 

[Bifferwine]

They do look like either sponges or tunicates. Does it have a siphon hole in the body?

 

[yote]

+1 Smitty and Biff