A person that has a dependance on human suffering, in a non-deadly, mildly inoffensive way. For instance, calling his/her pray names like "Bumbaclown" or forming insulting but simple sentences like "You piece of faecal matter". This is generally followed by a dead arm or a painful arm-lock.
It is generally thought that a 'Shippo' is someone of large physical strength or prensence, but not necessarily that intelligent. And will sometimes turn upon friends when bored.
Shippo: Alright idiot-head? *punch*
Victim: Ow, mate you are being such a Shippo!