Me and Marvin Gardens, by Amy Sarig King

Things I have in common with the Obe, the 11-year old boy who's the protagonist of Me and Marvin Gardens, by Amy Sarig King (Arthur A. Levine Books, January 31, 2017)

--plastic trash is vile, and picking up other people's trash is a normal and proper thing to do, and when you live near a creek you go down there lots and come home with your pockets full of trash.
--houses being built on beloved open space is vile.
--growing up isn't all it's cracked up to be, and being 11 when your friends are trying to grow up faster than you is miserable. (Especially for Obe, whose former best friend ended up punching him in the face in a territorial war that Obe didn't want any part of).
--science is cool, and "environmental scientist" seems like a fine career choice and learning science in school is better than doing math worksheets.
--families are complicated, but when it counts they have your back.

And both of us, me and Obe both, think that a new species of animal that's a kind of dog sized mishmash of animal-ness that eats plastic would be better if its scat wasn't corrosive enough to melt the soles of one's sneakers and create little circles of dead vegetation.

Obe finds this animal, who he names Marvin Gardens, down by the creek that's the last wild remnant of his mother's family farm (most of which got sold off, bit by bit, thanks to his Mom's grandfather's drinking problem).  Now a subdivision is being built on the beloved open space.  But down by the creek there's Marvin Gardens, a whole new type of animal.  One who eats plastic. 

Obe wins his trust, and studies him, while making friends with an over-protected neighbor girl who becomes his ally, and while hurting pretty badly from his ex-best-friend's betrayal.   The gang of boys Tommy hangs out with now are the sort that might hurt Marvin, and Marvin's corrosive poop and his plastic eating is drawing the attention of the builders and the neighbors...To save Marvin, Obe has to let the secret of his existence out into the world, the sort of decision that is its own sort of growing up in its recognition of responsibility and the inevitability of change.

So this is more than just a tree-hugging sort of story; it's mostly a story about coping with the fact of being an 11 year old in a tense and difficult world, and getting through it in such a way as to still have hope.  Which isn't to say its a depressing story, because there's lots about Marvin Gardens that's charming, and Obe's sister and Mom and science teacher come through for him very nicely, and his new friend is also a good addition to his life, and finally his mother realizes how bad his chronic nosebleeds are and gets him medical attention, and it was not leukemia which is what I was worried about....And Marvin Gardens finds a mate and makes more little baby plastic eaters (yay!).

But I think that, although there are universal themes here,  the audience that will most appreciate this book are the animal-loving kids who would never, never let a piece of plastic fall from their hands onto the ground, because sea turtles.

disclaimer: review copy received courtesy of the publisher and author at Kidlitcon 2016.