As Warmonger Contraption enters the battlefield, choose a creature type. Warmonger Contraption is the chosen type in addition to its other types. Warmonger Contraption's power and toughness are each equal to the number of creatures of the chosen type you control.
Well of Eternity enters the battlefield with X charge counters on it. At the beginning of your precombat main phase choose a color, then add one mana of that color for each charge counter on Well of Eternity.