When Mumbo turns you into a creature he says "Oominaka." Grant Kirkhope, Mumbo's voice actor, revealed that at the time of recording the voices for the game his left testicle was swollen. "Knackers" is British slang for testicles, so he thought it would be funny if Mumbo said "Ooh, my Knackers." Thus, every time that Mumbo uses his magic to turn you into a creature, he's actually complaining that his testicles are in pain.
"How are you feeling today?"
"Not good, I think my testicles are swollen"
*kicks him in the balls*
"Oominaka!"
"Oh, my testicles hurt!"
"Oh, my balls are really sore!"
"Not good, I think my testicles are swollen"
*kicks him in the balls*
"Oominaka!"
"Oh, my testicles hurt!"
"Oh, my balls are really sore!"
by historyodal August 25, 2013