Poison and Beast
Sphilis evolves from Caitlis. Its tail has formed a cobra-like head. It uses this head to seek out potential prey. It has the capacity to anything, but it isn't a savage. It quizzes its prey; tests it's intelligence. If the prey fails to answer correctly, Sphilis strikes. They have been poached because coats made from gold and blue make are highly valued.
I don't know why, but my two stage evolutions usually have a drastic change between those two stages.