Can jellyfish sting outside of water?
Short answer
Jelly fish can sting out of the water and even when they are considered to be dead.

Background
I do not have detailed scientific literature available. However, popular sources generally and equivocally warn against touching jelly fish, even on land and even when they appear to be dead. In fact, dead box jelly fish can be as dangerous as live ones (ABC News).

Credible sources
 - National Poison Control Center
 - UK Telegraph
 - ABC News