A DD pulled into a foreign port and put down maximum liberty. 

The skeleton crew didn't notice a chimpanzee, escaped from a nearby civilian transport, crawl up the mooring lines and then into the smokestack.

Down the stack, it made it's way into the engine room. 

It came across a power panel opened up for maintenance, couldn't read the warning signs, and with a bright blue blast shorted out the ships electrical system, and plunged the ship into darkness.

A little bit later, two junior Hull Technicians wander down with their flashlights, looking for the problem. 

They come upon the blackened body of the chimp.

They shine their flashlights on it's long burnt arms.

They look at each other. 

They highlight it's short legs and odd feet.

They look at each other again.

Finally one says, " Well, it's too hairy to be an electrician, the legs are too short for a Hull Tech,and there would be more tattoo's on a Bo'sun.  Call the wardroom and see if one of the Duty Officers are missing.