Spike

A spike is an attack in the Super Smash Bros. series and Super Smash Flash series that sends enemies downwards. Unlike meteor smashes, spikes cannot be meteor-cancelled, making them very powerful tools for edgeguarding and KOing opponents.

In Super Smash Flash
Although the "How to Play" tutorial mentions meteor smashes, meteor-cancelling is absent from Super Smash Flash. Therefore, the game only contains spikes.

Every character's up and down aerials can spike. Due to the instant-KO attack glitch, however, getting those moves to actually spike is considerably difficult; they will send static grounded opponents upwards, and may strongly semi-spike opponents who are moving horizontally. In order to properly spike opponents, one needs to hit an airborne opponent who is moving extremely slowly, or not at all.

In Super Smash Flash 2
In Super Smash Flash 2, every attack that sent opponents downwards was a spike, until the addition of meteor cancelling in demo v0.8a, where every attack that sent foes downwards became meteor smashes, instead.

Spikes were re-introduced to SSF2 in Beta 1.2.3.1. Players are unable to meteor cancel their knockback if they get sent flying by attacks whose angles are coded to be lower than 250°, or higher than 290°. This means that some moves will only spike in specific situations, i.e moves such as and 's forward aerial and  and 's neutral aerial multi-hits, whose knockback angle and strength depend on the user's current movement speed, may end up spiking opponents who get affected by both hits.

List of spikes by character
The list below only includes moves that can spike without needing to be affected by knockback stacking or other unorthodox situations.

Trivia

 * Prior to Beta 1.3, various moves, such as 's down smash, which deal more than one hit (one of them being a meteor smash), could end up spiking opponents due to how knockback stacking worked.
 * Before spikes were re-added to SSF2, 's down aerial contained a variable that turned its tipper hitboxes into spikes. The variable did not work, however.
 * Although spikes had gotten added already, Marth's tippered down aerial did not properly spike until Beta 1.2.4.0, potentially due to the fact that the "force tumbling fall" variable was set to true in the character's code.
 * G&W latehit spike.gif to Beta 1.2.0, several moves, like 's and 's [[down aerial]], will instantly end up spiking opponents during their descent, due to the angle of the attack's hit being significantlly increased, so late hits in most stall-then-falling, like Mr. Game & Watch's down aerial, moves will instantly end up spiking the opponents.
 * Rayman spike.gif to how the angle of the attack's hit has been significantlly increased from previous patches of Super Smash Flash 2, the initial hits of 's [[down aerial]] start spiking the opponents, along with the final hit of the move, which makes it impossible for opponents to escape.
 * The same distinction is shared with 's down aerial, as it instantly spikes the opponents at the late hit, along with the initial hit, because of the angle of the late hit of his down aerial being significantlly increased. The same distinction is potentially shared with other characters with stall-then-fall moves, as the late hit of stall-then-fall attacks will instantly spike the opponents; due to the angle of the attacks' late hit being significantlly increased.
 * The angle of the late hit of stall-then-fall moves and down aerials have been heavily decreased from recent and later patches of the game for respective reasons of spikes being occurred if the moves are used corrently in order to spike the opponents.