Pentakill is the League of Legends term for one player defeating all five opponents in quick succession, making it one of the game's rarest and most celebrated achievements. Clips of excited caster calls for these moments have long circulated among players, streamers and editors, who reuse them to punctuate highlights rather than explain the play itself. The BorisCaster2K15 name reflects that era of early gaming commentary, when short, hype-filled reactions were saved and shared as soundboard clips. It endures because the achievement itself never loses its drama.