Five animals you didn't know existed.
That's the title of the BBC video about rare animals.
Is Five animals you didn't know existed a NP or a clause with fronted direct object of the verb know, and with the subordinate relative clause (that) existed?
It is meant as a noun phrase. Interpretation as a clause is theoretically possible, with "Five animals (that) you didn't know" the subject of "existed". However, it is hard to read it this way, and such a meaning would in practice hardly ever (even never) be meant.
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It is meant as a noun phrase.
Interpretation as a clause is theoretically possible, with "Five animals (that) you didn't know" the subject of "existed". However, it is hard to read it this way, and such a meaning would in practice hardly ever (even never) be meant.
The interpretation "Five animals you didn't know (that) existed" is not possible, as far as I can see. This would be a