It must have been hard for Aaron to always be in his younger brother's shadow. We will see his frustration a bit later in Exodus with the whole golden calf incident.
By the way, in my spare time, I enjoy using Legos to re-create scenes from the Bible. Here, we have Moses turning the Nile into blood as Pharaoh looks on. I think I captured the scowl on Pharaoh's face very nicely, don't you?
(Just kidding ... I scarfed the picture off of the web someplace.)