Sweepers are Blotlings that largely resemble the Brooms from Fantasia. They carry buckets of thinner to throw at you, and will sweep you away if you get too close. They can be befriended by Paint and be destroyed by Thinner. You first meet them in the Jungle Boat ride. They are part of the Phantom Blot's Blotlings Army.
As seen in the picture, using a TV will distract them. They'll use their thinner buckets as a seat and watch intensly. Hitting them with anything (Paint, Thinner, Swing attack) will break them out of the trance and start attacking you again or go back to watching if you painted it.