Runnin' scared

You can do a fresh water dip and hope that that will "encourage" the hitchhikers to leave the rock, unfortuately mantis shrimp are little buggers, thankfully I've never had one (knocks on all the wood in the house, crosses fingers and toes)

You probably should have just answered your previous post, but...

Mantis shrimp are a reality on live rock. If you want rock that has a full variety of life, you need to risk them. If you don't want that variety, you can buy dead rock and get some life from established systems that will spread to the dead rocks. (Tufa, lace, volcanic, or calcium carbonate rocks are the usual picks). Garf sells something they call aragrocrete which is artificial rock for aquariums.

EDIT: Freshwater dipping live rocks makes them dead rocks...

Another trick is to use a biological control like a snowflake eel to eat any mantises on your rock. You could simply quarantine the rock for a very long time and then set up any of a variety of traps when you are sure the mantis would be hungry. Me, I set up a 10 gallon mantis tank and my wife snagged the rock she thinks it was in when she saw it and immediately moved it to the quarantine. The don't show up that much until they are big enough to be dangerous.

A quick freshwater dip does not kill everything off, I was not advocating soaking the rock, you just dip it in the water and take it back out, unless of course you have a second tank where you can isolate new live rock for a period of time until you can see what it may have carried to your door with it.

theres thi mantis trap at petsolutions.com its call x- terminator mantis shirmp trap,i really dont know if it works

The thing with traps is, if a Mantish shrimp doesnt get caught in the trap the first time, it will never get caught in that trap at all. Also they can survive 5 days out of the water, hence a fresh water dip may not even get it to move. Snowflake eels can eat them, but they also tend to eat stuff you want to keep.