If I play Fizz on my turn and play Existential Dread from trash, I want to play it repeated, do I have to pay the repeat cost of 2 energy or is it free?

To play Existential Dread repeated via Fizz, Trickster's ability, you must pay the Repeat cost of [2] Energy.

Here is the breakdown of how these costs work together:

1. Fizz’s Ability: When you play Fizz, his "When you play me" triggered ability allows you to play a spell from your trash (like Existential Dread) while ignoring its Energy cost.
2. Required Costs: Per the text of Fizz and RiftJudge FAQ #10668, you must still pay the spell's Power cost (in this case, [1] Power).
3. Repeat Cost: The Repeat keyword is an optional additional cost. According to RiftJudge FAQ #7297 and Rule 820.1.c.1, when you choose to Repeat a spell, you must pay the Repeat cost defined on that spell.
   • Even though Fizz allows you to ignore the spell's base Energy cost, he does not waive any optional additional costs you choose to pay, such as Repeat.
   • Therefore, to Repeat Existential Dread, you must pay the [2] Energy defined by its Repeat cost.

Summary of costs paid:

• Energy cost of Existential Dread: Ignored (paid [0] due to Fizz).
• Power cost of Existential Dread: Required (you must pay [1] Power).
• Repeat cost: Required (you must pay [2] Energy to use the Repeat effect).

Total Cost to play and Repeat: 1 Power and 2 Energy.