Trick or Cheat?

In the fourth book of the Alien Next Door series, Harris is excited to share Halloween with his alien friend Zeke, who doesn't need a costume because his alien form is costume enough. Zeke uses his powers to help Harris make the best costume he's ever had, while Roxy feels left out since she and Harris usually make costumes together. Harris is sure Zeke will win the school costume contest, but when another student tries to sabotage Zeke, it's up to Harris and Roxy to stop him.