bandwagon fan

A fan who claims he only liked a team because of a football coach or a certain player/s. If s/he becomes a fan of the team the coach or player joins, they're a bandwagon fan. If they do not become a fan of the coach or player's new team, and stopped liking their old team, they're a bandwagon fan. Fans who just want to be a pain in everyone's butt and be an antagonist by not cheering for the home team. You have the right to cheer for any team you want. However, to cheer for your hometown's rival just to be a prick is not cool.

The Ohio State Fan: Why don't you like Notre Dame football anymore? You once were a fan in 2005.

Bandwagon Fan who now cheers for LSU: I was just a fan of the coach, Charlie Weis.
The OSU fan: So you must have began watching him coach Kansas City Chiefs in 2010 right?
Bandwagon Fan: I never knew he coached the Chiefs.

The OSU fan: Your two favorite teams faced each other in the Citrus Bowl last year (2017). LSU vs Notre Dame. Who did you cheer for?
Bandwagon fan: LSU! Because I love Lousiana!
The OSU fan: But LSU lost.
Bandwagon fan: GO IRISH! I'm an Irish fan now!