Players fighting to reach the top of the structure created by the King of the Ladder event.
King of the Ladder
From the Hypixel Pit Wiki
King of the Ladder, or KOTL, is a minor event occuring in The Pit. The event lasts for 3 minutes.
When the event is active, a structure out of green hardened clay spawns in a random quadrant of the map. Standing on the structure rewards gold every second, with a higher rate of gold being rewarded at higher-up platforms. When more than one player is on a platform of the structure, the gold is distributed evenly between every player that is standing on it, incentivizing players to hit each other off. KOTL gives 2× gold and XP for kills and assists near the event zone.

Trivia
KOTL was added in The Pit 0.4 - Events Extravaganza. Twelve players were credited to its creation; players suggested names such as "Ladder Wars" or "Hard-point" for the event.
Standing on a King of the Ladder structure for more than 20 seconds in one event gives the player the "Up on top" achievement, worth 10 achievement points.