And while the cause of most of these sleep remnants is fairly obvious, the reason behind those sometimes-sticky, sometimes-crusty gobs of crud that can dot the lashes or cling to the corners of the eye is less clear.
Santa's Little Helper's initial appearance on The Simpsons was in the first episode of the series, Simpsons Roasting on an Open Fire, which aired on Dec. 17, 1989. Since then, he has become a recurring character.
The series centres on Wallace, a good-natured, eccentric, cheese-loving inventor, along with his companion Gromit, a silent yet loyal and intelligent anthropomorphic dog. Wallace was originally voiced by veteran actor Peter Sallis, but as of 2011, this role has been passed on to Ben Whitehead.