Because of their attentiveness, scanning eyes, and ability to manipulate objects in their environment, we often attribute human - or at least tetrapod characteristics to stomatopods. Alas, I fear the concept of "fun" is alien to them. Striking and manipulating noval items is probably just prey investigation - or construction and landscaping. Interacting with animals that they don't typically prey upon appears to involve territoriality or housekeeping. I've looked at "play" in stomatopods with one of the world's leading authorities on animal play and while the activities and motor patterns are there, I'm afraid the motivational factors are not.
Stomatopods have evolved to mate, care for their eggs and larvae, acquire and maintain a safe home, feed, and avoid or defend themselves from predators. This is basically what ethologists (animal behaviorists) used to call the "Four F's" - feeding, fleeing, fighting and ..... They do not seem to have the Fifth F - FUN.
Roy