Instant Transmission

Instant Transmission is, Kaiō-ken Goku and Super Saiyan Goku's up special move in Super Smash Flash 2. Goku performs a flip kick before teleport in the direction inputted by the player. The move has a fairly fast start-up time and intangibility frames during the teleportation.

The kick at the start deals 12%, considerable vertical knockback and slight horizontal knockback depending on which hitbox connects. With its speed and good knockback scaling it can turn into a good KO tool, especially against floats. If Goku is in Kaiō-ken mode it does 14%, and is slightly faster.

Super Saiyan version
Super Saiyan Goku's Instant Transmission is very similar to standard Goku's but has some different properties: it goes a shorter distance, only deals 10% and less knockback, always launches straight up, does not cause helplessness nor lag if landing on the ground and can be done repeatedly in the air. Additionally, by holding the special button Goku will perform a kick upon reappearing and if held longer he will follow up with a strong meteor attack. Both hits deal 10%.

Origin
In the Dragon Ball universe, Instant Transmission is a technique that allows the user, and anyone who is physically in contact with him/her, to instantly transfer from one place to another. It can be used to travel really long distances (such as going from a galaxy to another), to go from from the living world to the Other World (where the souls of the deceased go after death) and viceversa, and even to travel outside of time (as shown in Dragon Ball Xenoverse). However, in order to use the Instant Transmission, the user must first locate the ki of someone who is in the desired place at the time that the technique is being used.

Goku was taught this technique by the people of Planet Yardrat while he was training there after his battle with Freeza on Planet Namek. To locate someone's ki, he usually puts his index and middle finger on his forehead in order to concentrate. However, if the ki he tries to locate is too far away, he won't be able to use the Instant Transmission on his own. For example, when he tried to find the Namekians' new planet after the destruction of the first one, he needed the help of North Kaio (who can see everything that is happening on the North Area of the Universe) in order to locate it.

While this technique is primarily used by Goku as a means of transport, he has also been shown using it for combat, such as when he instantly teleported in front of Cell in order to hit him directly with a Kamehameha.

Trivia

 * In v0.9b, there was a glitch that caused Goku to fly very far after executing Instant Transmission as Kaiō-ken finished, often leading to SDs or giving Goku a very large extension to his normal recovery.