A Super Mode or "Overdrive Mode" where a character temporarily becomes much stronger, almost always accompanied by a visible change. Basically, a Dangerous Forbidden Technique or Deadly Upgrade without the dangerous/deadly parts — it may be limited somehow, usually by time or a finite Power Source, but sometimes it's not even that (if it shortens the user's lifespan or similar, it's a Heroic RRoD). Very popular in action-based video games. May or may not have a requirement to trigger.