I ran some numbers: a hand containing Expedition Map, Urzas Power Plant, Once Upon a Time, and four expensive cards will assemble Urzatron on Turn 3 64.5% of the time on the play and 70.5% of the time on the draw
It happens any time it becomes day or night, not just during the untap step
Expect 15% appreciation in 2025 with Z-A tie-ins
(1) You cannot Special Summon monsters for the rest of this turn after this card resolves, except with Spell effects, also add 1 Overload Fusion from your Deck to your hand, also the maximum number of attacks per Battle Phase this turn of any monster you Fusion Summon using 6 or more materials with Overload Fusion this turn is equal to the number of materials used for its Summon
Without it, youll be stuck with a lackluster hand and wont be able to use your entire deck before the match is over
Even if you dont draw a colorless land, you can still cast it as a 2/1 flier (that cant block)