Say A does something to B that causes B to have an additional trait.
For example, A cooks B to add the trait "cooked" to B; A damages B to add the trait "damaged"; or A hugs B to add "hugged"; etc. as in "B is cooked/damaged/hugged".
What is a word to describe A? ...I'm thinking "applicator"? The main effect that I'm going for is that A is adding something new to B's list of adjectives.
EDIT: the word for the action that A takes, ie. "drive", needn't be the root word for the trait that B is given, ie. "driven", which is a valid interpretation of how I posed the question. I am, however, looking for the general term, just to clarify :D