Anticheat

Anticheat is a system to 'stop the hackers'

When a player hits another, a 'bot' will sometimes appear (It can't be damaged)

If a person hits that 'bot', the Anticheat message (Hacks have been detected on your client, staffs are watching etc.)

will appear and the player's hits will not register for 3 seconds.

This seemed to stop aimbot/killaura hackers, but this system almost only checked Defaults, and seemed to ignore Donators

Hypixel Hit Detection got worse because of anticheat - some people say this, but there doesn't exist solid evidence.

Also, Defaults were totally angry about this anticheat because it showed up randomly and usually made them die.

Now, it is influenced by your network level, and hits everyone, but donators still get a slight advantage.