Set in the modern days, one night the sky is suddenly lit up in a mysterious bright blue glows that fades off almost immediately. It seems that somehow the event caused a mutation in one of the protein found in many domestic animal including those in cages. The mutated protein contains free radicals but usually stay dormant but once daybreaks, their body begins to produce more of these proteins and the blue wavelength of light would energise the free radical so that the electrons tend to entangled into pairs. Unfortunately this entangled state is prone to upset by the magnetic field generate from our household appliances leading the poor animal to suddenly go berserk and exhibit aggressive behaviour. Given this scenario which pet would pose the greatest threat to us?
Bonus: Any one who can resolve the mechanism behind these bizarre phenomenon with good hypothesis gets to name the mutated protein. (reply to StarfishPrime's comment)