Nephtor and the Rabbit Men (Book #1 of a Series)

This horror story takes place in San Francisco, Paris, and Beijing. Triplets from the planet Neptune have been expelled to Earth due to an amoebic infection that made their brains concave. Most of the day, their brain is in a constant Shake, but a random hour each day, it is in Quake mode. While in Shake mode, all cells are traversing the cerebral cortex, and anyone they touch becomes joyous. But during the dreaded hour of Quake, any person they touch turns into a devious human-sized rabbit.