That’s zombies AFk leveling.
RO Alchemist Homucli Afk Leveling Enhanced xD.
Summon a mob of zombies.
Eat Pizza.
Have 5% more exp XD.
Cant see it effective sith the exp given.
Just try other class with dps
hello fellow RO and GE Players!! 
they already nerfed the zombies btw that was CBT2 video i believe