p - Block CTCP:
This will prohibit others from sending you ctcp commands. You will see ctcps that are sent to rooms that you are in, but you won't reply to them. This mode is useful to prevent ctcp flooding or just annoying ctcps. Ctcps are used to measure lag or gather information about someone, such as what client they are using. Operators can bypass this mode.
Privilege: Users
Examples:
/mode Dan +p
/umode +p