Cow1337killr is a player spoof of an adventurer that makes numerous appearances in RuneScape.
- Before the tour's removal, Cow1337killr could also be found in the Rellekka Hunter area catching Cerulean Twitches during the Gnomecopter Tours.
- He can be seen in the cutscene during the Animal Magnetism quest. He kills an Undead cow, and after being shooed away, he attempts to kill a Sneaky undead fowl during a cutscene. However, he hits a zero as the chicken dodges his attack, and deciding he'd be safer with Alice's husband, runs straight toward him.
- He also makes an appearance in the Festival of the Dead event and provides the player humorous information about his fellow player spoofs.
- He can also be seen in RuneScape's "Vote NO, RuneScape Free Trade & the Wilderness" YouTube video, with a collection of other npcs.
- Cow1337killr, along with other player spoofs did not receive a graphical update following Evolution of Combat.
- He wields a non-updated version of the Dharok's greataxe that has a rune colouration.
- His name is leetspeak for Cow elite killer.