To use, a player discards the Skip card on their turn and chooses the player who will lose a turn. Skip cards have only one purpose: to cause another player to lose a turn. It must remain as that card until the hand is over. Players can use as many Wild cards as they want as long as they use one natural card. Original print runs of Phase 10 had two Wilds in each color to reduce confusion, current print runs use black Wilds.
A Wild card may be used in place of a number card and can be used as any color to complete any phase.