Near the start of the episode, Ned's mom tells him to go to the store to buy Tomato Paste and to "change those dirty clothes." He runs up to his room and uses his orange shirt as pants and blue jeans as a shirt. After he feeds Newton, get ready if you don't have it on tape. If you don't have a tape, then be prepared to quickly look for the slip-up after Newton states something about the house being really big. After that scene, a scene of Ned running out of the house is shown (he moves offscreen after a split second), but for some reason he's wearing his orange shirt as a shirt and his blue jeans as pants again (and it returns back to Jeans-Shirt and Shirt-Pants for the remainder of the episode)! To see this easily, just use a VCR and freezeframe.