Hiphophippo said:
I'm going to ignore the second, descriptive part of your story and believe that the picture posted is what they saw.
That would be much cooler
Muggers: "Give me your valuable possessions good sir!"
*Scorpion appears*
Muggers: "On second thought, I remember I left my oven on!" *tactical retreat*
OT: Those muggers were asking to get ninja'd (not the forum verb, the getting your ass kicked by a ninja verb) mugging someone by a ninjitsu school.