The grey number indicates how much colourless mana is needed, meaning any colour can be used
Caution is advised however, it is not just that hardest global pump spell to play with but one of the riskier ones as well
Because of a fact, that Captains trigger is conditional, its conditions, which is P/T will be checked on its resolution, which means that we need to resolve it before Fabricate
Cold-Eyed Selkie Cold-Eyed Selkies made rounds in EDH since the dawn of the format, punishing anyone foolish enough to play islands in their deck (youre not getting out of this one easy, Hallowed Fountain)
That opponent can't cast spells or activate abilities during that turn, and Sen Triplets' controller can play lands and spells from that player's hand
You can be silly and make a mostly-ramp Codie, Vociferous Codex deck