Link's bomb, a character-specific item, can be thrown at other opponents, where it will explode on impact. The character hit by the bomb will take about 6% damage. If the bomb is dropped, then other characters can pick it up and use it as an item. The bomb can also be caught by other characters. When the bomb is flashing red, that indicates that it is about to explode. If a bomb explodes on the character holding it, then they will take a minor amount of damage. As the bomb is an item, Link cannot use the move if he is already holding another item. Link's bomb is unique in the fact that it can deal damage to anyone, including the user's team members.
Damage throughout the series
Young Link's Bombs
Young Link's bombs are exactly the same as Link's, but they hit multiple times. They also have a slightly different design.
Toon Link's Bombs
Toon Link's bombs, based on Link's bombs but with a Wind Waker-inspired design, can be thrown at other opponents, where it will explode on impact. The character hit by the bomb will take anywhere from 5% to 9% damage. The blast has a larger radius than Link's and has a more cartoonish appearance, based on Toon Link's appearance. If the bomb is dropped, other characters can pick it up and use it as an item. The bomb can also be caught by other characters. When the bomb is turning yellow, that indicates that it is about to explode. If a bomb explodes while a character is holding it, the person holding it and people in the immediate vicinity then they will take reduced damage, around 3%. It is interesting to note that while Link's bombs deal damage to breakable terrain such as the towers of Shadow Moses Island, and the floors of the Skyworld, Toon Link's do not. As the bomb is an item, Toon Link cannot use the move if he is already holding another item. Similar to Link, Toon Link's bombs can also damage team members.
The bombs that Toon Link throws use graphics from The Legend of Zelda: The Wind Waker.
The bomb has appeared in almost all Zelda games, including the original The Legend of Zelda. However, the bombs have been largely reduced in size. Link holds his bombs in one hand in the Super Smash Bros series, while in his respective games, he holds them with both hands over his head, since the bombs were much larger. The bombs flashing red when it is about to explode also comes from the Zelda series. The bomb design is based on the Link's respective game he appears in.
If the attack button button is held during an animation where Link/Young Link/Toon Link cannot throw his bomb (such as during a roll, or during the time when he takes out the bomb), it will allow the player to do a forward smash with the C-Stick without throwing the bomb. The bomb can then be thrown after the smash, stunning the opponent and setting the opponent up for a dash attack, slide smash, or a dash attack cancel.
In Brawl, if a Bomb explodes while in knockback, it increases the knockback Link and Toon Link travel. However, if Link or Toon Link use their Grab Air right before it explodes while in knockback (other than the knockback of the Bomb), it cancels all knockback allowing them to survive at percents they'd usually get KO'd for that move. However, it is very situational because it takes 7 seconds for a Bomb to explode and the attack that knocks them has a chance of making them dropping the Bomb. Without Link or Toon Link having a way to force the bomb to explode, there's rarely a chance of pulling it off with a result of surviving longer.
Bomb to Aerial
Bombs can also be used to setup aerial attacks. When a bomb is thrown or z-dropped on a airborne opponent underneath, the opponent will be sent upwards for a guaranteed aerial follow up. The most commonly chosen follow ups are Link's nair for its speed and his dair for its KO power. Toon Link's down air is notable for being a meteor smash. As such a bomb can be used a effective spike setup, provided the opponent is close enough.
In Melee, bombs dropped by Link can explode when hit. This can be useful in that Spin Attack can collide with the bombs and deal damage, to Spin Attack again. However the spin attack must be fresh in order to deal enough damage to detonate the bomb; hitting an opponent with a spin attack merely once before using a bomb recovery will lower the move's damage output too much. Additionally, this does not work effectively in Brawl, as bombs cannot be damaged by the user's attacks to make the bomb explode.
Normally, if a bomb is dropped from midair, it will explode once it hit the ground or an opponent. However, if Link/Young Link/Toon Link drop a bomb extremely close to the ground, the bomb will stay there, similarly to a dropped grenade. The simplest way to do this is to short hop, then drop it at the opportune moment. It can also be done by dropping it while jumping up through a platform or dropping down from a platform. Occasionally, a platform will be high enough for one of the Link's to just throw up from the ground.