Gorilla Crab!!!
hairly brown sharp-pinchered creatures straight from Reef Hell....
Had to deal with one many years ago that rode into tank on some LR.
Shredded feather dusters, killed snails and even had an appetite for zoa's...if did not eat them, just pulled them apart for fun.
Not only deadly, but also very quick and smart.
Took me many hours over a few days to finally catch it. Used every kind of trap found on web for catching such a thing...
No luck. It was quick, fast and smart, usually disappearing for hours after tank is approached or something new in it...like a trap...glass, bottle, whatever.
Finally made a miniature crab trap like I have out in garage, bridle veil stretched over a small circle of wire...multiple lines...baited with good sized piece of fresh shrimp...
Shoved trap under sand so only shrimp sitting on surface....
Then waited, waited and waited some more before the crab approached bait...
When it finally tasted shrimp, would not let go of it, and easily pulled up and out of tank.
Crab still resides in my freezer somewhere....
Get mad...go on warpath....devote all spare energy and time to getting the little murdering SOB out of tank...(unless you enjoy seeing all your pretty corals and inverts eventually ripped to shreds...
)
Good Luck!
Gorilla crab 
