Beetles are special items from the Zelda franchise. They are carved in a real beetle's shape, hence their name.
This item was introduced for Super Smash Bros. for Nintendo 3DS and Wii U. It was revealed on Sakurai's Miiverse page and simultaneously on the current Super Smash Bros. Official Website. The Beetle originates from The Legend of Zelda: Skyward Sword. It was used to pick up things from a far distance. In the Smash series, it can be thrown (and hit back at the thrower) to carry the grabbed fighter off the stage for a KO.
The Beetle is an item which can be thrown at opponents. It will travel in a straight direction until it hits an opponent. It will carry them into the air past the Upper Blast Line, taking a stock and potentially Star KO them. However, if the opponent who is targeted the Beetle hits it with enough force, the Beetle's direction will change. Also, the grabbed person can Button mash to escape, with the task becoming harder the higher their damage
The Beetle returns as a throw able item functioning mostly the same way it did in the previous game. Aesthetically the beetle now causes a instant Screen KO in most stages (This can be an indicator of Screen KO availability.) when the Beetle successfully carries a fighter off the stage, and during the Screen KO, the Beetle can still bee seen attached to the player while they hit the screen. In addition in Ultimate the Beetle now is affected by Weight. This means that characters such as Zelda are taken up by the beetle faster than heavier characters such as Link are, giving lightweights less time to escape from the Beetle's grasp. Metal Box's increase the weight of characters, significantly slowing down the lifting speed of lightweights such as Zelda while heavies such as Bowser can not be taken all the way depending on the upper blastline.
A remote-controlled item shaped like a little bug, Link used this item in his adventures to collect far-off items. In Smash Bros., tossed Beetles will fly straight ahead, grab foes, and carry them into the sky. If one grabs you, wiggle with all your might to break free!
- Wii - The Legend of Zelda: Skyward Sword (11/2011)