djinsane,
Merged your threads.
If you are absolutely certain you have a mantis shrimp, you have alot of rock, and you can not track down the rock it is in, then:
You are likely going to need a rubbermaid tub and either club soda or high specific gravity water(1.035 worked for me).
If you dip the rock in high SG water the mantis will typically come out quickly.
If you pour the club soda over the rock the mantis will typically come out quickly.
I prefer the high SG method.
I have not had good luck with traps, but some folks have used them with success.
Lot's of folks will be interested if you can catch him and get him back into regular level salt water quickly.
Please post such and offering in the selling or trading areas on Reef Central.
Have some fun.