Spring

The Spring is an item that appears in Super Smash Bros. Brawl. Like a few other items (Peanut, Peach, etc.), the Spring does not appear regularly like a typical item, but appears after a certain attack - in this case, Sonic the Hedgehog's Spring Jump. If Sonic does this in mid-air, the spring simply falls off the stage. However, if he performs it on the ground, the spring temporarily sticks where it is, allowing other players to use it. Presumably, it will disappear after a certain amount of time, similar to the Bumper or Flipper.

Super Smash Bros. Brawl Trophy Information
An item used to assist jumping. Jump on it, and it will send you bounding sky-high. You can also toss enemies onto it. It originally appeared in the second stage of Donkey Kong Jr., where it was used as a shortcut to leap to a distant platform. It resembles the bouncing projectiles that appeared in Donkey Kong, but those are said to be actually jacks, not springs.