Ike (SSBU)/Neutral special
Ike raises his sword, Ragnell into the air, with blue fire flowing on the blade, then quickly drives it into the ground, creating giant flame geysers. This attack can be charged for extra power, KO'ing middleweights at around 55% while fully charged. However, the fully charged version damages Ike quite a lot. The attack also has transcendent priority, meaning it beats every move in the game. The move creates up to 3 pillars, depending how long it's charged for.
The move, being a slow, chargeable attack, has one use:edgeguarding. The attack hits below the ledge, meaning that if Ike has time to charge it, it can be a devastating two-frame option, albeit requiring precise timing. The move can also be useful when the opponent is recovering from moderate heights, Ike can use eruption to catch the opponents landing in certain scenarios.
However, this move isn’t very practical outside of edgeguarding due to it's slowness. Additionally, Ike can only use Eruption if the opponent is far way from the ledge and low enough so that Ike can charge up eruption and hit the attack, as the uncharged variant is rather useless, only KO'ing at percentages where going for other, more reliable options is better and safer. The fully charged variant can break full shields, however, the charge time is extremely long and will realistically never hit. Ike can also not charge eruption every time the opportunity presents itself, as it will become predictable, making the attack lose effectiveness. Additionally, missing the attack is dangerous, as it allows for Ike to be punished.
Overall, Eruption is impractical in most scenarios due to it's slow speed and uselessness when uncharged, however, it's one use, edgeguarding, is a valuable and powerful use case, and is not to be underestimated.