Figment

The Nightmare in Clockwork Town is a large, not-so-friendly Spider. You’ll have two main encounters with her; Once in Enigma Hills after you complete the large Gear House puzzle, and then at the very end of the Clockwork Town section, atop The Clock Tower. 

The first time, she will spawn little spiders that you’ll need to fend off as quickly as possible. After about 3-4 little Spiders, the Nightmare herself will fall down onto the platform, but will be on her back. Hit her a few times until she gets back up. This will repeat until she has just under ¼ of health left.

When you fight her again, you will on top of a platform with 4 main gears (1 large middle gear and 3 smaller gears surrounding it. When the fight starts, the 3 smaller gears will rise up. You’ll need to fight of a few small spiders before the Nightmare jumps up into the air. When she does, stand close to one of the small gears. Where she lands is where her shadow will appear so you want the shadow to be on one of the small gears. When the shadow appears, roll out of the way and she’ll come crashing down, lowering the gear she hits. Repeat this process until all 3 small gears have been lowered. Once they have been, a bridge to the right will appear. Cross the bridge and hit the Pendulum into the Nightmare. 

The trophy will unlock after the small cutscene.