I'm going to cause a kid to have a bad grade in our group project
Wouldn't that affect the whole group's grade?
I do not think so. We all get individual grades, so forget that kid.
Working in groups is the awful but trying to get somebody to have a bad grade is wrong. It could affect their grade and their future.
I'm happy if I was able to ruin their grades and demoralize them.
I think it's wrong to intentionally cause him harm like that. You should just let it go and request they aren't a part of your group in the future.