I hopped in to ATL after the revert this morning to hit the Void Pool and I think my first drop was around wave mid-20s which I chalked that up to barely being able to hit anything before it died from the bot chains. For this event (in the void pool) since the hats aren't anything special/rare to collect, I wasn't even keeping track of how many I got as I was trying to kill stuff. Once it ended (I think around wave 90) I netted about 30 hats which could probably be higher if I switch up the template I'm using. Sampires becomes hard to use after wave 70 because you are doing so little damage (when you can actually hit) to leech back life/mana.