Dark Welcome

[Lunar Origins]

Dark Welcome

[ Trap ]

Target 1 card on the field:  That card's effect is replaced with this:

• Once per turn, your opponent can choose and discard 1 card from their hand.

Simply stupid and effective.

[Darj]

You can simplify the effect further with:

 

Target 1 card on the field; the effect of that target becomes "Once per turn: Your opponent can discard 1 card".

 

And I agree: the card is simple yet effective. It basically negates anything that is not a Counter Trap, at the cost of a card in your hand. The discard effect may be optional, but of course the opponent will be using it unless you are running DWs.