Special Summon 1 "Time Thief" monster from your hand.
During your Main Phase: You can banish this card from your GY, then target 1 "Time Thief" Xyz Monster you control; attach 3 "Time Thief" cards of different types (1 Monster, 1 Spell, and 1 Trap) from your GY to that monster as material.
You can only use 1 "Time Thief Startup" effect per turn, and only once that turn.