Bat and the End of Everything Book by Elana K. Arnold

Bixby Alexander Tam (nicknamed Bat) has been the caretaker for Thor, the best skunk kit in the world…but the last day of third grade is quickly approaching, and Thor is almost ready to be released into the wild.

The end of school also means that Bat has to say good-bye to his favorite teacher, and he worries about the summer care of Babycakes, their adorable class pet. Not only that, but his best friend is leaving for a long vacation in Canada.