To defeat this Boss, if you don't have any Slows or Pauses double jump onto one of the three ledges on the outside of the area. Don't worry about Time Crystals. He can't get you here. Then move to one side and when he turns his back shoot. But don't stand too near the edge of the platform because he can get you with trash there. Hit him three times like this. Don't be impatient, though, because this is a time-consuming strategy.When he shoots out trash suck it up because sometimes it gets in the way of your shots.If he shoots two consecutive bits of trash, avoid the second one before sucking them up.