Which is correct: "another think coming" or "another thing coming"? [duplicate]

Solution 1:

The full phrase is if you think x, you've got another think coming.

Wiktionary notes on usage:

This expression is used as a rebuke, often in constructions similar to "If X thinks that Y, he/she has another think coming!" Sometimes the word got is included, in the familiar constructions has got and have got, as "(someone)'s got another think coming", "they've/you've got another think coming".

The form to have another thing coming is often seen, and may have been aided by a mishearing of the /k/ of think blended with the /k/ of coming, making think sound like thing.

Solution 2:

In looking through the Ngram results (which heavily favor think), I stumbled across this very interesting excerpt from a book that addresses this very question:

Other idioms in English are so opaque semantically that they have undergone phonological modifications possible only because speakers could not even identify the component words. While some speakers say, "if you think X, you have another thing coming," other speakers swear the correct form is "...you have another think coming," each group doubting the very existence of the other dialect group until confronted with a living member of it. (Nicolas Ruwet and John A. Goldsmith, Syntax and Human Experience)