The Baby Quetzalcoatl Stave is a Tremodesummoning weapon dropped by the Brutallisk that summons a baby Quetzalcoatl to fight for you.
Its best Modifier is Ruthless. The Mythical modifier provides the widest array of stats 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 Baby Quetzalcoatl Stave has over a Ruthless one is knockback.