Panda Ray — Michael Kandel

Christopher Zimmerman sure looks like a normal ten-year-old (even if he is the shortest member of his class). He collects pebbles and has a dog named Buzz. He also tells his whole fifth-grade class at Lincoln Elementary about traveling into the past to see dinosaurs and trilobites. For Christopher - in spite of his ordinary looks - is actually the youngest child in a family of aliens... or are they mutants? (And really, does it matter which?)
When Mother hears of Christopher's boasting, she rules as she must: Christopher will be scooped out.
That's right - no more omicron for him, no more upsilon.
Christopher would rather die than be scooped out, so he enlists Gramps's help and flees on a journey through space, time, and other less recognizable things, and into a classic science fiction adventure.