G's idle animation deals 500 damage in Street Fighter 5: Arcade Edition but you have to wait roughly a minute for it to happen
Impractical doesn't even begin this... but it's a cool Easter egg
Idle animations in Street Fighter 5: Arcade Edition can actually have varying effects. Birdie will flick a booger at the opponent for light damage and Akuma will strike a pose that will also hurt the enemy if they stand too close.
Ibuki will even restock a single kunai through her idle animation. Thus far, these have been completely and totally impractical in a real match. There's no reason for the opposition to wait for this action to occur if you aren't doing anything.
With the addition of G and Sagat to the roster, both characters come with their own idle animations. G's in particular is very interesting as it also has a quirk that can be comparable to Birdie or Akuma's.
If the opponent stands real close to G when he performs this action, they'll actually take 500 damage and launch them! If for some reason it's a counter hit, then it'll inflict 600 damage instead.
Even if the aforementioned three's idle animation had some practical purpose, there's absolutely no way we'll ever see G perform this in a real match. Using my stop watch, it took roughly a minute and five seconds for this to happen.
G can even combo into this attack. If you didn't have to worry about G's V-Trigger timer running out, it'd actually be possible to perform a 100% damage combo on 1,000 health characters. This assumes you got the counter hit on it too. Completely impractical.
Click image for animated version
Source via Reddit. Sent in by: Captain_Fire_Feet, giru017, and Negatomsk.