Insidious Will

The copy will have the same targets as the spell it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. If, for one of the targets, you can't choose a new legal target, then it remains unchanged (even if the current target is illegal).

The controller of a copy can't choose to pay any alternative or additional costs for the copy. However, effects based on any alternative or additional costs that were paid for the original spell are copied as though those same costs were paid for the copy.

If you choose new targets for the target spell or for the copy, the new targets must be legal.

If the spell that's copied has an X whose value was determined as it was cast (like Eliminate the Competition does), the copy will have the same value of X.

The copy is created on the stack, so it's not “cast.” Abilities that trigger when a player casts a spell won't trigger.

The third mode can copy any instant or sorcery spell, not just one with targets.