Lantern Flare

You can't cast a spell for both its cleave cost and another alternative cost. For example, if an effect gives an Alchemist's Retrieval in your graveyard a flashback cost of {U}, you can't cast it from your graveyard for its cleave cost.

If you cast a spell for its cleave cost, that spell doesn't have any of the text in square brackets while it's on the stack.

If you're paying the cleave cost, you choose the value of X.