Robin Goodfellow in English folklore is a euphemistic personification of a half-tamed, troublesome elf or hob-goblin, a prankster who is the domesticated aspect of Puck (cf. Puck).

There is a reference to him in Shakespeare's Midsummer Night’s Dream, ii. 1.

Either I mistake your shape and making quite,

Or else you are that shrewd and knavish sprite

Called Robin Goodfellow...

Those that Hob-goblin call you, and sweet Puck,

You do their work, and they shall have good luck.

The earliest reference to 'Robin Goodfellow' cited by the O.E.D. is of 1531,

The name Robin is Middle English in origin, deriving from Old French Robin, the pet form for the name Robert. After Meyerbeer's successful opera Robert le Diable(1831), neo-medievalists and occultists began to apply the name Robin Goodfellow to the Devil, with appropriately extravagant imagery.

The character originates in German Folklore.

According to the public domain 1898 edition of Brewer's Dictionary of Phrase and Fable:

[Robin Goodfellow was a] "drudging fiend," and merry domestic fairy, famous for mischievous pranks and practical jokes. At night-time he will sometimes do little services for the family over which he presides. The Scotch call this domestic spirit a brownie; the Germans, kobold or Knecht Ruprecht. The Scandinavians called it Nissë God-dreng . Puck, the jester of Fairy-court, is the same.