Thread:ScaryMovie53/@comment-33286111-20180525022834/@comment-33286111-20180525182438

Muntz was insane and thought Russel was trying to steal the credit for finding the bird.

Affably evil does NOT mean, doesn't do evil things. There are plenty Affably Evil Villains who do very heinous things.

Muntz's initial friendliness was genuine, he turned against them because they mentioned Kevin and Muntz assumed they were secretly rival explorers.

When Muntz though they were rival explorers, he wasn’t polite. Again A Faux Affably Evil villain is polite only for an ulterior motive or to unnerve their opponents.

Muntz was truly nice to anyone he thought was trying NOT to steal the bird. Basically he's friendly so long as his paranoia button isn't set off, at which point he gets murderous.

You need to rewatch the movie.