Some typos don't show up very often, or hardly ever appear at all, because the words they're meant to represent simply don't occur with much frequency themselves. Such near invisible typos include the pairs Wale* + Wail* (only three in OhioLINK, all false hits in one way or another) and Wales + Wale (which also got three hits, two of them legit). In the 1933 James Whale classic The Invisible Man, Una O'Connor gives a whale of a performance. She plays the the Irish innkeeper's wife and I'm not sure which is more disconcerting, listening to her shrill banshee-like wailing after "seeing" the Invisible Man, or watching Claude Rains disrobe into total nothingness in her sitting room. There were 13 cases of Invisb* in OhioLINK and 113 in WorldCat. Take a look in your own catalog today and, by fixing any you see there, render this typo invisible. For now. Just remember to keep an "I" (or three, or five) on (or in) it.
(The Invisible Man movie poster, from Wikipedia.)