Joker

When Joker is on the battlefield, all creatures gain Weaknesses. {r}>{g}, {g}>{u}, {u}>{r}, {w}>{b}, {b}>{w}. Colorless creatures do not have Weaknesses. Creatures with multiple colors suffer from all of
their Weaknesses.
When a creature is damaged by a source they are
weak to, they become tapped and gain a Down
Token.
If Joker is the commander, your deck may have
cards of any color.