Special Summon 1 "Ultimate Flagship Ursatron" from your Extra Deck by banishing 1 "Ursarctic Big Dipper" and 1 "Drytron Fafnir" from your hand and/or field, although you can banish 1 of them from your Deck instead if "Ursarctic Polari" or "Drytron Alpha Thuban" is on the field. If you would Tribute a monster(s) to activate an "Ursarctic" or "Drytron" monster's effect, you can banish this card from your GY instead. You can only use this effect of "Ursarctic Drytron" once per turn.