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One Mutant Plant PC turned NPC has Simple Tendrils.

It seems to indicate weapon use, but it doesn't say how many, or if extra attacks are gained?

I didn't see any monsters with this mutation, so I don't have anything to go on.

I think I found the answer to my own question, GW 1e has manipulation vines, of which there are 2d4 and can attack with weapons up to 12m (36 feet) away!