To the best of my knowledge, we can say "That's what is called camouflage."
If I'm not wrong, here what means "the thing which." So, the sentence makes sense. But I just need a native English speaker to verify that the following sentence is also correct.
That's what that's called‌: camouflage.
Please notice that in the latter sentence there is a colon.
Best Answer
That "trick" of using a colon before camouflage is misleading. Generally speaking, in written forms, that refers to something previously mentioned. For example...
In my example, the first that simply functions as a "pronoun", standing in for the word camouflage.
The word what also effectively functions as a pronoun (it just refers back to the first that).
The second that isn't quite so simple, in that you can't say it represents one or more preceding words. Loosely speaking, it stands in for the fact that (or, reason why) the zebra has stripes.
The actual punctuation in OP's sentence is a matter of style. Valid alternatives include a comma, period, or dash (they all just represent a "break/pause" in speech). The important thing is that either [whatever is being identified as camouflage] should already have been mentioned in the discourse, or the speaker should be pointing at it as he speaks
It's sometimes okay to use that as a "forward reference" for something you haven't yet identified by anything you said or wrote earlier, but this would normally require a very strong implication that the speaker (and probably his audience, too) are at least thinking about whatever that refers to, even if they haven't specifically mentioned it.
Assuming that OP is concerned about whether he can validly use that twice in the same utterance, the answer is "Yes". In this specific example, they refer to two closely-related referents (a word, and the thing represented by that word). But the referents can be completely different...
...or they can both refer to exactly the same thing...