This wacky warp in World 4-2 lets you use a pipe instead of the vine to go to the World 6/7/8 Warp Zone. First, use the vine teleport glitch to get Mario on the right side of the screen. Then, go down the third pipe after the vine, and instead of dropping you into the coin bonus room, the pipe will take you to the Worlds 6/7/8 Warp Zone.

You can also use a variation of the walk through walls glitch to get Mario on the right side of the screen. Inside the narrow brick passageway at the beginning of 4-2, jump straight up twice so that Mario breaks two brick blocks directly above him [screenshot 1]. Next, slowly walk to the right until the space that you just created in the ceiling has has scrolled about halfway off the left side of the screen. Go all the way back to the left side of the screen [screenshot 2], then duck and jump once. Mario's feet should automatically catch the wall, and he will appear to be stuck [screenshot 3]. Release the Down button, and Mario should start to slide through the brick wall, so wait for him to stop at the right side of the screen [screenshot 4]. When Mario has stopped sliding, jump out of the wall and head to the vine area on the other side of the pit. Go down the third pipe [screenshot 5], and voilà -- Warp Zone! [screenshot 6]