The Starlight Staff is a Hardmode sentry-type summoning weapon that is dropped by Twinkle Poppers. It summons a Twinkle Popper sentry to fire stars in many directions above it. Said stars will not move far, but will deal significant damage.
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 Starlight Staff has over a Ruthless one is knockback.