Monster Mediums - Oil Pastel

This is Düc. Düc is from Vietnam, but has lived in America for three years.  He is very proud of the meaning of his name. Düc means moral or good. He lives by this every day. He is a kind friend. He listens well. And he always encourages his friends. One thing that is hard for Düc is that he cannot hold still. He has a hard time sitting for long periods of time. As long as he can be moving, he is happy and fun-loving. Düc is in fifth grade and his favorite thing to do by far is plan the playground. He can do things that other kids can't. He can cross the monkey bars, fly off from the swings, and jump from platform to platform with ease.

Can you guess what medium Düc is?