Space Stone

When Space Stone enters your battlefield, Exile
your hand face down and draw three cards. If
you lose space stone, discard your hand and
return all cards from your exile zone to your hand
{t}: Cast a spell from your face down hand without
paying its mana costs. Use this only once a turn
{5}:Gain Control of space stone. Any player may
activate this ability
At the Beginning of your end step, if you control
all six infinity stones, exile them, then meld them
into "Infinity Gauntlet"