2004-10-04

You choose the target when this ability is put on the stack, but you do not decide whether or not to pay the mana until the ability resolves.

2022-12-08

You choose the target when Lightning Rift’s ability is put on the stack, but you choose whether to pay the mana as the ability resolves. Once you make that choice, no player may take actions until the damage is dealt and the ability has finished resolving.