From the game Super Mario World for the Super Nintendo
This glitch is not so exciting, but gets a fairly high number on the exciting-ness scale because it is very useful. It is also a part of two of the glitches that are later on this page. The glitch is fairly simple. You can use basically any two items for this glitch (we have only tried it with p-blocks and koopa shells but we're sure you can use more). However, you can not do it with two koopa shells or two goombas. Also, this is difficult with goombas because they will often get up and hurt you. Place one item down. Now, take the second item and try to place it down at the exact same place as the first. Now, back up a bit and run at the two items, holding Y. If done correctly, you will pick up both of the items, though it may not look like it. You can then set them both down and use them separately. This glitch can be difficult with koopa shells because they are easily kicked away. It helps to put down the shell second and crash into the first item and then put down the koopa shell. Be ready to jump if you're trying this glitch with a koopa shell and you're near a wall...
Submitted by: kornyhatemachine and Connie
A Youtube video of the glitch can be seen here.