Question
How big can you grow? What do you do when at your biggest size?
Answer
I actually do not know how big I can grow by myself, I am pretty tall by default, and more than often other growth spurts are caused by sudden magic infusions!
Guess it'd depend on how strong those infusions are.
As for what I'd do? Well, it'd be interesting to visit one of the much much larger cities of the human when even larger than my normal height. Imagine the chaos I could cause by showing up at several kilometers in size. Bet they'd be able to feel the tremors of my steps before I even show up far in the horizon, just taking a slowy step with a forceful impact on purpose to make it even worse.
Yes, that seems like fun, give them tiny humans a little scare!