The Butterfly Staff is a craftable summon weapon. It summons 3 random butterflies, at the cost of 1 minion slot, that seek out and attack enemies. Like other minions, summoned butterflies are invincible and follow the player for an unlimited amount of time, unless the player dies, summons a replacement minion, or cancels the buff.
Its best modifier is Ruthless. The Mythical modifier provides the widest array of stat bonuses, but these primarily affect the initial summon rather than the resulting minion. Additionally, Minions cannot deal critical hits. The only significant advantage a Mythical Butterfly Staff has over a Ruthless one is knockback.