Infinite throw trap
The infinite throw trap, abbreviated as ITT, is a technique in which Donkey Kong grabs the opponent repeatedly without throwing them. This technique is possible to perform in the original Super Smash Bros. on all characters besides Mario, Luigi, and Pikachu, who can all recover out of it. It can also be done in Super Smash Bros. Brawl on Lucas and Ness.
In Super Smash Bros.
After grabbing an opponent, Donkey Kong can use his unique forward throw to begin carrying the opponent over his shoulder, an action which deals a small amount of damage. During the "cargo carry," Donkey Kong can walk around with the opponent and can choose to perform a cargo throw if the opponent does not escape via button mashing. Once the opponent struggles free, if Donkey Kong is standing still, he can grab again almost immediately. The opponent has a few frames in which to escape or counter. The pattern repeats as follows: Donkey Kong grabs the opponent, initiates the cargo carry to deal some damage, the opponent struggles free, Donkey Kong grabs again, and so on.
The ITT is sometimes banned in competitive play because it leads to stalling.
Once the ITT is started, it is almost impossible to escape. The fact that Donkey Kong has the fourth longest horizontal grab range (behind Samus, Link and Yoshi; also the longest non-tether horizontal grab range) and widest vertical grab range (which allows Donkey Kong to grab short hopping opponents) adds to this problem.
But most importantly, many consider the best counter strategy is refusing to escape the grab. If the grabbed character doesn't button mash, they will stay latched on until the Donkey Kong throws. Because the damage is inflicted when Donkey Kong grabs, when faced by the ITT, many opponents will refuse to escape, leading to a stalemate in which the Donkey Kong, intending to infinite, waits for the opponent to button mash, and the grabbed character, not wanting to deal with escaping the infinite, waits for the Donkey Kong to throw.
However, it is important to note that the technique is escapable. At high enough damages, the opposition will get knocked down from the release, allow them to tech. Even though it doesn't look like it, the release has knockback, but no damage. Formerly, it was often banned, but recent tournaments appear to ignore the tactic altogether. But since most high level Smashers can escape the infinite, it usually doesn't make a difference.
In Super Smash Bros. Brawl
The Infinite Throw Trap returns in Brawl, but now can only infinite on Lucas and Ness due to their unusually long grab release animations. All characters will now break free after a certain amount of time, even without button mashing.
Smasher Isai demonstrates the Infinite Throw Trap around the 0:14 mark.