when you play the card every player must pick up cards from the draw deck until he/she picks up a card of the color you announced. for example: if I put down a trap card and called blue, then everyone must pick up cards from the draw pile until they get a blue card (even if they already had blue cards) the color in play is now blue.
This must be a new twist on UNO cards, I have not heard of a trap card
Try this website for UNO variations
when you play the card every player must pick up cards from the draw deck until he/she picks up a card of the color you announced. for example: if I put down a trap card and called blue, then everyone must pick up cards from the draw pile until they get a blue card (even if they already had blue cards) the color in play is now blue.