The Quarter Attack is a move that appears in Sonic Adventure and Sonic Adventure DX: Director's Cut. It is a technique used by Chaos 4, where it splits its body apart and uses the separated parts as projectiles.
When using the Quarter Attack, Chaos 4 splits its body into four separate parts, which it then launches at opponents as water orbs.
In gameplay, this technique is used during the Chaos 4 boss battle. When preparing to use this attack, the Chaos Emeralds will leave Chaos 4's body before said body splits apart and shoots the parts one by one at the player. These orbs can be avoided by simply moving out of their way. If the player is hit by this attack, they will take damage.