Which temporary League of Legends mode debuted as a 2014 April Fools' Day prank?

Ultra Rapid Fire was the temporary League of Legends mode that debuted as a 2014 April Fools’ Day prank.

Riot Games introduced URF on April 1, 2014, presenting it as an intentionally chaotic alternative to standard League gameplay. The mode dramatically reduced ability cooldowns and removed or eased resource restrictions, allowing champions to cast spells at a frantic pace. It was initially available for only a short period.

The joke became more successful than a typical seasonal gag because players genuinely enjoyed the fast, exaggerated rules. URF’s popularity turned it into one of League’s best-known rotating game modes, returning in different forms over the years. Some versions use random champion selection and are called ARURF, or All Random Ultra Rapid Fire.

Doom Bots, One for All, and Nexus Blitz were also limited-time modes, but they did not originate as the 2014 April Fools’ debut described here. URF’s defining identity is its deliberately broken-feeling speed and ability spam.