Link will take out a bomb that can be thrown that an opponent and will explode after a set time, or on impact. The bomb has different attributes depending on which version of Link is using them.
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. In SSB4, however, if Link hits an enemy with a thrown bomb, he will take no damage even if he is in the blast radius. 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.
The bombs from Smash 64 and Melee use graphics from The Legend of Zelda: Ocarina of Time. In Brawl, and SSB4, Link's bombs are from The Legend of Zelda: Twilight Princess. In Ultimate, Link’s Remote Bombs are based on their appearance in Breath of the Wild, and are remotely-controlled detonated rather than detonated on a fuse, due to the way bombs work in that game.
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 and are smaller, making it a smaller projectile hitbox but makes it harder to see when thrown.
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 to match Toon Link's appearance. If a bomb explodes while a character is holding it, the character holding it and characters in the immediate vicinity will take reduced damage, around 3%. His bombs glow yellow and fluctuate in size to indicate that it is about to explode.
While the bomb has limited capabilities on its own, it can lead into a Quickdraw after a short hop, and can aid in Toon Link's recovery. If the bomb is dropped, other characters can pick it up and use it as an item. It can also be caught and thrown by other characters. Toon Link can also set the bomb on the ground by dropping it right before landing, or right after a ledge jump.
It is interesting to note that while Link's bombs deal damage to breakable terrain such as the towers of Shadow Moses Island, the organic bridge and pillars of Brinstar, and the floors of 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.
In Ultimate Toon Link's bombs are slightly more volatile than his counterparts, immediately exploding on impact with floors or other surfaces even when z-dropped from a short hop or thrown lightly, though they may still land on the ground should he drop them after taking a hit.
Toon Link's Bombs use graphics from The Legend of Zelda: The Wind Waker.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
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 Hand 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 Links to just throw up from the ground.
If the attack 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.
The bomb dash  is a glitch that can be performed in Super Smash Bros. Melee by either Link or Young Link. It is done by taking out a bomb and then short hopping off the stage to grab the ledge. Then, perform an edge hop. Before landing, drop the bomb with Z. Then, perform everything once more and if performed correctly, the bomb should dash across the stage.
Bombs are operated by being placed on the ground, and in several games they can be picked up and thrown: a few seconds after its activation, a bomb starts flashing and finally blows up, creating an explosion that, in addition to destroying walls and obstacles and damaging enemies, can damage even Link himself. They are however much larger than they appear in Smash: rather than holding them in his hand, Link has to carry them above his head with both arms. In most games Link can carry a limited number of bombs in the inventory, though replacements can be dropped by enemies, found in chests or bought in stores.
Link's Giant Bomb custom could be a reference to the Super Bomb which appeared in The Legend of Zelda: A Link to the Past, an enormous bomb which Link has to lug around the overworld and which is required to access specific areas. While the Super Bomb itself made no further appearances, later games introduced similar items like Exploding Barrels.