#ricochet trap

Ricochet Trap

In his last seconds, Remhas regretted using his most powerful spell.

In his last seconds, Remhas regretted using his most powerful spell.

So first of all, yes, this can work if the spell whose target is being changed can legally target Ricochet Trap (i.e. a red instant spell on the stack).

So, let’s say you go to Lightning Bolt your opponent, but they try to counter your Lightning Bolt with Dispel. How rude... Of course you won’t stand for this and so you cast Ricochet Trap targeting Dispel. 

When Ricochet trap resolves, you get to change Dispel’s target. Changing the target isn’t optional so we have to change the target if possible. Let’s look at your options: All three spells on the stack are instants, which is a good start. Dispel is already targeting Lightning Bolt, so choosing that wouldn’t be changing the target. Dispel can’t target itself because a spell can never target itself. That only leaves Ricochet Trap which is still on the stack even though it’s in the middle of resolving right now. So you change the target to Ricochet Trap and then Ricochet Trap finishes resolving and goes to your graveyard.

When Dispel now goes to resolve, its only target is illegal (because it’s no longer there) and so Dispel is countered on resolution. Lightning Bolt then goes on to resolve as intended.