Wario (SSB4)/Side special/Default
Wario summons a bike from under himself, then begins riding. When riding the bike, he can alter its speed, change direction, pop a wheelie then slam down, taunt, and jump off. It is a very versatile move, being able to help Wario recover, edgeguard, ledgetrap, be used as a pseudo-projectile, jablock opponents, anti-air opponents, camp, perform situational combos, or even outright kill opponents. It is the only heavy item that can be summoned by a character, and thus the only heavy item used in competitive play. When using the bike, although rather negligible, Wario gains knockback-based armor for up to 20 KB. This means Wario is able to power through very weak moves such as the multihits of PK Fire, Shakunetsu or Meta Knight's rapid jab. The bike can be destroyed after taking 18% total damage. If the bike is destroyed whilst Wario is on it, he will be put at an awkward launch angle, which can lead into a followup against him.
The earliest that the hitbox can come out is at frame 21, slower than even his forward smash, by 3 frames. Combined with its relatively poor hitbox, this hinders its effectiveness as an approach option greatly. During the ride, he can change the speed of the bike, with the lowest speed having no hitbox, and then, once it starts gaining speed, it'll have a hitbox, and it'll increment from 1% up until max speed, which then it deals 7%. It also has a smaller and weaker hitbox that only works on aerial opponents (whereas the bigger and stronger one works only on grounded opponents), making it a good combo tool in the air. If used in the air, Wario is unable to turn the bike or do a wheelie, but he can rotate it slightly left and right. Wario can start the bike right next to a ledge, and the bike will drop down in the air at the slowest possible speed, although still having a weak hitbox. This makes it good against recoveries, and is able to combo into forward air or Waft. If the bike hits a wall, it'll continue riding for a while if it happened on the ground before dropping down, or it'll immediately drop if it hits a wall airborne. Wario is also thrown off the bike from this as well.
The wheelie is often used in conjunction with the ride hitbox, or as an anti air. If Wario performs a wheelie right after hitting an opponent with the ride hitbox, he can combo into the wheelie, doing usually about 16%. The hitbox of the wheelie is also possesses great range, and since it goes upward, it makes a decent anti-air. After the rise, Wario is able to hold the wheelie for a finite amount of time, before being forced to slam down, although he can slam down earlier by pressing down. During the hold of the wheelie, there is a weak hitbox on the back of the bike that only hits grounded opponents, and while not very useful, it helps wheelie be more safer if it misses. Afterwards, Wario can slam down with the bike, which provides a very slow, but powerful hitbox, capable of killing middle weights at ~80%. It is also possible to slam offstage, although it is extremely hard to hit.
The drift of the bike is relatively powerful and disjointed, and has a late hit that hits multiple times. It is unable to hit aerial opponents, however, which greatly hinders its usage. If a drift is used without any direction inputted, it will automatically go at its slowest speed.
The bike also works as an item. It can be eaten by chomp, thus healing Wario and decreasing the charge time for waft. It is also possible to attack the bike, in which it'll eventually explode, with bike parts sporadically flying out, which can also be eaten, and if more than one are eaten, it in fact heals Wario more than the actual bike. As a heavy item, it is slow to throw. It is able to be thrown in all 4 cardinal directions, and smash throwing allows the bike to be thrown greater distances with increased damage and higher velocity. It has high damage output and almost no knockback, even at 999%, making it very useful in jablocks. It also provides use in edge-guarding, as the low knockback forces the opponent to be sent down, unable to act for a short while due to hitstun. If a bike is left onstage and Wario isn't close to it, he will perform a looking animation, and be stuck in lag unless he reaches a certain fallspeed, in which it can be cancelled. If Wario performs side special next to a downed bike, even if it is from another Wario, he will put it back up and ride it,
Wario is able to perform numerous tech involving the bike, most of which are essential to playing him.
Hitbox duration extension
While not a mechanic exclusive to the bike, it greatly helps Wario with ledgetrapping, as he can use waft on the bike to extend the hitbox duration for an absurd amount of time. Coupled with the power and disjoint, it is very effective at 2-framing and catching almost any ledge option. It also extends Wario's super armor frames.
Instant bike spawn
If Wario performs bike right after running off a ledge, the bike will be propped onto the stage and Wario can act normally. This is especially useful when the need to use a bike setup or the bike as a projectile arises.
Bike jump cancel
When Wario jumps off the bike in the air right before touching a wall, he can instantly land on the ground and perform any action. This is useful when recovering to surprise opponents, or dodge attacks like charged smashes if used with a defensive option.
Aerial bike speed increase
If an aerial bike is used at a ledge or platform, and it touches the ground right when you go upwards, he will gain a significant increase in aerial speed with the bike, and thus perform better combos or camp, as it is also hard to punish up close.
Aerial bike drift
If the bike is performed right at the edge of a stage or platform whilst facing it, then Wario turns the bike at a specific timing, he can perform a drift in the air. Afterwards, quickly changing direction will allow Wario to do continuous aerial drifts, as long as he doesn't hit a wall. This has little to no practical use, as the drift does not hit aerial opponents.