BOMT is amazing! We read it in small groups in grade 6 although its a grade 5 text.
This lesson is done to match the standard addressing how characters change in response to events or conflicts with plot. I recreated this chart on chart paper.
The first two columns are to be done while reading part 1 of the the change he has gone through. book. The middle is to make predictions of what will happen once he is hit with the snowball. The last 2 columns are to demonstrate
On the attached one I have the firs two columns prefilled since we did it together but you can erase if you'd like your students to start from scratch.
I had students do this and complete it as a homework assignment. Give students a "character trait" reference sheet to use as well.