now unfolding themselves into limbless monsters of pain.
I guess this may contain a verb, unfolding and a subject, themselves so maybe I may not discern it a phrase. So I guess I may mostly discern it a non-finite subclause (dependent clause[?])? I maybe thought a dependent clause contains a subordinate conjunction or a relative pronoun placed in a first word placement. unfolding may seem like a participle. This may somewhat seem like a participle phrase. And I think it contains a verb and subject so maybe not? now may seem an adverbial complement to unfolding and may get me somewhat.
Now unfolding into limbless monsters of pain, his thoughts came (hastily[?] (not sure if came gets discerned transitive).
This may seem like maybe a participle phrase, no subject themselves?
Unfolding into limbless monsters of pain, his thoughts vexed him.
I think this may mostly seem a participle phrase, (no adverbial complement now that may get me), no subject.