The natural habitat of the Typo Fairy is the milliseconds between one hitting submit and one's writing appearing on the internet. His presence is marked by the cry, "But that wasn't there the last five times I proofread this!"
I once encountered the Fairy in person in my City of Heroes days:
Kauket: You! You're my archbenesus!
Kauket: hbgtyv6 *
Typo Fairy: My work here is done.
When I looked up again, he had disappeared.
(* Results of face planting in keyboard.)
In attempting to categorize the taxonomy of this anthropomorphic personification, I have speculated upon a possible relationship to Death. Similar to the Death of Rats subcontracting a specific aspect, perhaps the Fairy is the Death of Words; however, as the Fairy does not TALK LIKE THIS, I have come to believe he is more akin to the Verruca Gnome, a bringer of undesired gifts.
Currently there are no known methods by which to avoid a visitation from the Fairy. If any reader should discover a means, please inform this author immediately.