Sleepy

Sleepy is a supporting character on Once Upon a Time, and a member of the brotherhood of dwarfs that accompanied Snow White in several adventures. As his name indicates, he is always presented as being tired and sleepy, but is nevertheless an active member of the group, enjoying his work at the mines and adopting an adventurous spirit when it is required. Following the Dark Curse, Sleepy became trapped in Storybrooke, Maine as Walter, a security officer at the local hospital, who shares Sleepy's main characteristic.

Season 1
When David Nolan goes missing, Sheriff Graham, Emma Swan and Mary Margaret Blanchard ask Walter to view the security cameras. Sheriff Graham asked if he or Leroy saw anything suspicious, but tells them that he hasn't. Leroy jokingly says it would have been because Walter was sleeping. It is then revealed that David woke up from his coma and walked into the woods by himself.