Mantis shrimp traps

[balistidae]

I am hearing a loud clicking coming from my tank. I havnt lost any livestock but i cant figure out what the click is other than a mantis shrimp. Has anyone tried one of these traps? If anyone has one kickin around could i possibly borrow it? THanks, Greg

[Delphinus]

Could also be a pistol shrimp? I'm not sure how to tell which one you've got though other than getting lucky and spotting it sometime.

[smellsfishy]

i don't know there name but i have the candy caine (red and white strips ) snails and they will aggresively spin there shell back and forth in a circle which will also make a clicking on the glass as well, it fooled me for months, until i actually saw it.