While helping Dudibus with their
Star Wars set, I had an idea for a new type of split spell punisher mechanic that gave you the expensive half if an opponent couldn't bare the cheaper half. They're designed so that the cheaper half is an active negative for the opponent but the expensive half is a potentially bigger problem. You can always cast the expensive half for full value, but you can tempt the opponent with the cheaper half.
Walk Softly Instant (U)
Destroy target attacking creature unless its controller begs for mercy.
(If they do, add the mercy half of this card to this spell's effects.)~~~~~
Carry A Big Stick Instant - Mercy (U)
You may put an equipment card from your hand onto the battlefield. If you do, you may attach it to a creature you control.
Stop Instant (U)
Counter target spell unless its controller begs for mercy.
(If they do, add the mercy half of this card to this spell's effects.)~~~~~
Smell the Roses Instant - Mercy (U)
Look at the top four cards of your library. Put two in your hand and the rest on the bottom.
Keep Calm Sorcery (U)
Target player discards two cards unless they beg for mercy.
(If they do, add the mercy half of this card to this spell's effects.)~~~~~
Carry On Sorcery - Mercy (U)
Search your library for a card, put it in your hand, then shuffle your library.
Don't Drink Instant (U)
Target player can't gain life for the rest of the game unless they beg for mercy.
(If they do, add the mercy half of this card to this spell's effects.)~~~~~
Drive Instant - Mercy (U)
Add
. This mana doesn't empty as phases and turns end.
Come Back Sorcery (U)
Gain control of target permanent you own unless its controller begs for mercy.
(If they do, add the mercy half of this card to this spell's effects.)~~~~~
See Us Sorcery - Mercy (U)
Draw X cards, where X is 1 plus the number of players. Reveal your hand. Starting with the player on your left, for each player, put a land card from your hand onto the battlefield under that player's control.