Following on from thyrs, another possible supernatural being...

Pixey Green in Stradbroke is clearly related to the form Phykessaegrene in an undated deed (AD C5689, possibly as early as the 13th century).   Ph- here is clearly the scribe's eccentric spelling for P-, since he also wrote Phyctel for "pightle".

Could this be an early reference to pixies, first recorded in OED in 1542?

Keith