Item pickup glitch
To do it, Mr. Game & Watch has to walk or Wavedash towards the item and start a neutral attack. As he glides into the proximity of the item, Mr. Game & Watch will start picking up the item. He must then be stunned by an attack or by touching a Mushroom during this pickup process.
Some items such as Food or the Warp Star will behave in a special way as they will travel through the stage and opponents and be unaffected by gravity when thrown. They can be dropped on the ground normally by pressing Z. You are able to press A to attack while carrying such an item.
Items affected by the glitch are listed here.