Spring

From the Super Mario Wiki

The Spring is an item that appears in Donkey Kong Jr., Mario vs. Donkey Kong, Donkey Kong and Super Smash Bros. Brawl. In 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 to the stage, damaging anyone unlucky enough to have it dropped on them. However, if he performs it on the ground, the spring temporarily sticks where it is, allowing other players to use it. It will disappear after approximately six seconds.

There is also another Spring in the game, which is modeled after the Mario series. Unlike Sonic's Spring, this Spring is a normal item that appears in the game regularly. If jumped on, a player will be launched in the air extra high than with a normal jump. If the Spring is knocked on its side, however, the player will be launched sideways.

In Mario vs. Donkey Kong, the spring appears in many levels, including some boss battles. They are often needed to clear levels. They are placed on the ground or sometimes in mid-air.

[edit] Super Smash Bros. Brawl Trophy Information

Type	Image	Description
Spring		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.