Shonen Upgrade is a common trope in, well, Shonen series. It's an item, power, or transformation gained by a main character to drastically increase their abilities. Most commonly it's some sort of "special ability" or "new move," like a Super Mode. It sometimes appears as an Eleventh-Hour Superpower, a Dangerous Forbidden Technique, or, rarely, I Am Not Left-Handed. See also New Powers as the Plot Demands. In Mecha Series, the equivalent is the Mid-Season Upgrade.