Spooky Day: All REDs are turned into Skeletons (Snipers) and can only use Melee (Ammo boxes do nothing). However, their melee attack is faster and applies the "Scared" debuff. Basically the same debuff from HHH's boo.
Total Control: BLUs are given constant crits, increased reload speed, faster movement speed, and have slight overheal. REDs never lose Rebeller effects if they grab ammo and they do less melee damage. Believe it or not, there are a lot of people that would love doing this, either as a challenge or because they want guards to have a potentially flawless round.
Reverse Hide and Seek: BLUs lose their ammo and have to hide in places around the map, meanwhile, REDs can grab ammo from the armory after the cells open. The Cells stay closed for 2-3 minutes, after which they open and BLUs get slowed down considerably. REDs cannot get LR from this round.
Deadly Touch: REDs can insta-kill with their melees. They are slowed down, however, and have reduced melee attack speed.