Bismuth, Weaponsmith

Whenever a creature you control deals combat
damage to a planeswalker or a player, put a
forge counter on Bismuth, Weaponsmith.
{t}: Remove any number of forge counters from
Bismuth. Add {x}, where X is the number of the
number of forge counters removed this way.
Spend this mana only to cast artifact spells or
to equip Equipment.