invert id

Just saw this today and was wondering if anybody had an idea of what it was.

Really curious what these are. I've searched the internet on and off endlessly over the past few months to no avail. One or two has turned to a couple dozen and I'm wondering whether I need to take action. They haven't died off like pineapple sponges usually do. They look like a cross between a...

Found dude bro in my tank. Not sure what he is, if he’s harmful or what he eats but I didn’t put him there and my puffer is very interested in him. He took a couple bites out of him in the video. But he has tiny little black eyes and what seems like a hard back the puffer couldn’t bite through...

Is this something I should worry about?

Hello, anyone know what kind of cowrie this is? Thanks in advance.