This article contains plot details from Unlocked.
Boo Boo is a stuffed animal Boobrie that Elwin gives Keefe during Keefe's stay in his house (Splendor Plains) during book 8.5: Unlocked. Keefe stays there because of the development of his new power and he doesn't want to go back home. Boo Boo comes from Elwin's large Stuffed Animal Collection room. Not much else is known about Boo Boo except that Elwin named him.
Boo Boo is a black-and-yellow stuffed bird with a mohawk, and has long, curled eyelashes (like a boobrie).