Over the past few days, the #wikimedia IRC channel has been hit with persistent spam in the form of pings. A solution could be to have a bot kick or ban users that ping more users than a set limit. Some users would have to be whitelisted (jouncebot).
freenode does run a bot that prevents flooding (known as Sigyn). Previously, we did have its predecessor (idoru) on #wikimedia iirc but apparently the new bot Sigyn is not present. We could probably ask freenode staff to enable it at #wikimedia.
Either way, you'll probably need approval from IRC group contacts or channel contacts.