ravenning

erratic, unpredictable and threatening - possibly motivated by uncontrolled primeval instincts - rage, hunger, lust or even madness

(You have to make the verb up first to develop the adjective. I started using it as a gerund to describe my new puppy's behaviour to friends. It is marvellously onomatopoeic as nobody seemed to have any trouble understanding it as an assumed existing word.)

the dog was a ravenning monster