Pixie

The little green blur in the picture of Piper in my RotG folder? This is a closeup of what she looks like.

Pixie forgot her own name around 200ish years ago. It was unfortunate that Piper forgot it as well but to be expected. Pixies have a notoriously bad memory for everything excluding what they attach to. Pixie attached herself to Piper and consequently forgets day to day things except when Piper reminds her.