A person who gets really mad when they are sleepy. They also generally look disheveled. They might bite or otherwise harm you if you approach them while sleeping.
Grumplestiltskin over here bit me because I sat next to her on the couch while she was asleep
My girlfriend was laying in bed because her head was spinning from the vodka she drank so I had to have her stand up to give her the grundle stiltskin she would never forget.