The Warp Star (ワープスター, wāpu sutā) is an item appearing in Super Smash Bros. Melee, Super Smash Bros. Brawl, Super Smash Bros. for Nintendo 3DS and Wii U and Super Smash Bros. Ultimate that sends a player flying off into the sky and crashing back down into the stage when picked up. It is possible to control the landing location by pressing left and right on the Control Stick. Because of this, it's possible to miss the stage and self-destruct. If a character is hit hard when the Warp Star is first grabbed, the item can be "dropped" before it can be used. The Warp Star can then be grabbed and used normally. A shield will not protect against the star's impact, except for Yoshi's shield, so the only way to avoid damage is to not get struck. A factor that most people forget is that the player is invincible while "on" the Warp Star. Since Warp Stars crash into the stage from above, they can be used to "leap" to a higher part of the stage. Therefore, stages with many platforms can limit its effectiveness (and, in the case of scrolling stages with high off-screen platforms such as Rainbow Cruise or Rumble Falls, can even cause an SD).
The Warp Star originated as Kirby's ride: it helped the ponderous puffball get around at high speed. Hop on the Warp Star in Super Smash Bros. Melee, and your character will rapidly launch up off the screen. You'll return in a flash, causing an explosion as you hit the ground. Try holding a direction to alter your landing!
The Warp Star's ability to travel left and right before landing seems to have been diminished from Melee to Brawl. In Melee, it could travel farther left or right, which often results with jaded Brawl players to SD.
A warp-speed item. In the Kirby series, Warp Stars are used to move between stages. In Smash Bros., they're ultrafast attack items that zoom up and down to devastate anyone they hit. You can shift your landing spot by moving the Control Stick left or right during your descent. Choose your target and hang on! Don't overshoot the mark and plummet off the stage, though.
A magical transportation device that Kirby uses to get around during his adventures. In Smash Bros., jumping on one will send you high in the sky and then crashing back down to the battlefield. Anyone caught in its path or landing spot will be sent flying, and the rider can even aim it a bit!
Game Boy - Kirby's Dream Land (08/1992)
SNES - Kirby Super Star (08/1996)
In Brawl, if one pauses the battle at the right moment as they go off-screen, they can see most of the stage to the point of seeing it beyond the stage's boundaries.
If a player uses the Warp Star and runs into Jigglypuff'sfinal smash, on the way up, they will still receive knockback from the attack.
It's likely this is where the Kirby universe icon comes from.