Obtained by beating every wave up to wave 23 (after u beat 22) without dieing
Every round you survive gives you a random buff or debuff or a debuff or buff to an ally who has died (at a 60/5% - 25/5% chance for you to get a buff or an ally to get a debuff or buff)
Ammo reservation
Endurance
Well fed
Featherfall
Heartreach
Drunk
Inferno
Invisibility
Ironskin
Life force
Magic Power
Mana regen
Summoning
Swiftness
Thorns
Wrath
Rage
Any of the flask effects
The nebula armor boosts at tier 1
The nebula armor boosts at tier 2
The nebula armor boosts at tier 3
or
Literally any debuff
Leveling up causes it to apply buffs for an extra minute and debuffs for an extra 5 seconds