SOLVED. Children's/YA - boy helps a shapeshifting alien track down another alien (not Animorphs). [s]

[Registration08734]

I read this book somewhere between 1995-2000. It was for older kids, but not graphic or scary.

It takes place on Earth. It's about a shapeshifting alien who recruits a boy to help him track down another, potentially criminal or renegade, alien of the same species. The aliens' normal form is maybe a slug (it's not Animorphs).

I don't remember any of the plot involving tracking down the other alien, only a few minor details:

The alien helps the boy with his schoolwork - it's able to transmit thoughts to him while sitting on his head, and it teaches him about photosynthesis by showing him a glowing diagram of the process. I think the boy has a model of The Spirit of St. Louis hanging from his ceiling, and the alien sleeps on it.

At one point, the alien turns into a large dog to intimidate some older kids who are bullying the boy. He scares them by having the dog walk on its front paws, and write its name in the dirt.

The good alien's name is maybe Zak or Zeke.

Any help is appreciated, thank you!

[SBC]

Could it be Shape-Changer by Bill Brittain? Two seventh-grade friends help Zymel, an alien, shape-changing policeman from the planet Rodinam as he tries to recapture an alien master criminal (Fek) who can also change form. Their original form is something like a blob of grey Jell-O.

[Registration08734]

That's it! Thank you so much, this has been bothering me for years!

[SBC]

Glad I could help :)