Socker:

Sockers are sock shaped creatures that only appear when there is a child in need. They function as imaginary friends, of sorts, and can be summoned whenever the child feels lonely or scared. Sockers typically stay loyal to their friends—they don't refer to them as customers or clients—though, when the child reaches an age where they don't need the Socker anymore, they move on to the next child. Sockers have the ability of advanced memory programmed into them upon creation, which is why they remember everything about their past friends, and hold it with them until their death—which only occurs when they have helped a total of 100 kids for the better.