If he is a smasher...
I would set up a small tank, some larger crushed coral and rock rubble substrate, possibly some rock with holes. A simple power compact lamp is fine, lots of bright light isnt real good for em.- (again, thats just I would do, I like these guys)
adding some cool algeas and corals would be fine too.
Im just saying they are very easy to take care of and very entertaining. Theres also the educational aspect. Most people dont even know about em, let alone get to see one.
Maybe even a place in the sump?
check out the mantis forum, they are pretty cool creatures.