slug id

I’ve had my 130 gallon aquarium for like 2 months and I have only introduced 2 clownfish and a Bicolor Blenny. Some days ago I noticed some little snails in the tank and I think they are Cerith so they are good. But today I saw this thing and I don’t have idea what it is.. help!

Hoping someone can identify what this invert is and if it’s harmful at all. Looks like a slug with a soft shell, snail without a shell.

Just saw this black round slug looking thing in my DT today. Not sure where it hiked from but it was about the size of a dime. Has retractable antenna and can move at a good rate. Kill or live?

I got 20 pounds of live rock that came with a ton of cool mushrooms and I put it in my qt this morning when it was still dark I saw this caterpillar looking creature that is red with white spots and horns I've looked for hours what it could be but I haven't matched a picture yet can you help...

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...

Hey all, I’m transferring some stuff into another tank and seen this guy slithering? Anyone know what the heck this creature is?

I think I will need your help with these new neighbors. I call Google and have a beer while searching but I can't find what kind of starfish or slug it is. I only have one guy here because the other one was too shy for a photo shoot. Also these 2 pictures are the best I can take due to the...

My snails have been mysteriously disappearing so I cleaned out my sump today and found this in the rocks can someone help identify this? I suspect this has been leaving empty shells around my sump

I was watching my tank while feeding and saw some movement. I'm new to the hibby so I don't know a lot of different organisms.. anyone know what this is?? I think it might be a sea slug (cuz it moves just like a snail or slug) but I cant find anything that looks like it online. Should I be...

Happy Super Bowl Sunday! I was getting through some weekend maintenance before the big game and noticed this black object embedded in some Zoas. Didn’t think much of it until I noticed it had little antennas. I’ve never seen a black worm/slug like this before. Any thoughts?