Sci-fi children's book with an alien football mascot named Mookiee?

Question

I remember when I was EXTREMELY young, I read a very non-descript children's book with an alien character named Mookiee who served as the mascot of a middle-school football team on Earth. I can't really remember the plot but I do remember that Mookiee's eyes had rotating colors in them that were (possibly) having something to do with his powers. Does anybody know what I'm talking about?

Answer 1

This sounds very much like Aliens in the Endzone, the second book in the Screammates series, published in 1998.

The plot concerns a middle-school American football team called "The Rockets". From a Goodreads review:

Johnny Nielson is the star running back on his youth football team, the Rockville Rockets. They reeled off seven wins to start the season, but are currently in a slump that could cost them a shot at the state championship. Their school principal has a solution: the introduction of a team mascot, a strange-looking green man named "Mookie the Martian."

It turns out that Mookie is a real alien, who escaped to Earth to get away from a bully. Unfortunately it turns out that a rival team also has a new mascot - who turns out to be Mookie's old bully, Vandor.

Vandor has a deal for Mookie: if Rockville wins the championship, Vandor will leave him alone permanently. But if Westport wins...Vandor will destroy the planet. The two aliens take turns meddling in the game action, the score staying close as the clock ticks toward the end. Johnny and Kristen are the only players who know what's at stake, but can they deliver the winning play under pressure, saving both Mookie and Earth from Vandor? It all comes down to a final field goal attempt...