What is the chain when I play Arcane Shift on my Fizz?

When you play Arcane Shift targeting your own Fizz, Trickster, the resolution follows a specific sequence where the spell's instructions are executed, and Fizz's "When you play me" (WYPM) ability is added to the chain as soon as he enters the board.

According to Rule 336.1, you must execute a chain item's game effects in their entirety. However, if an action during that resolution (like playing a unit) triggers another ability, that ability is added to the chain immediately as a pending item.

The Resolution Sequence:

1. Cast Arcane Shift: You target your Fizz and an enemy unit. Arcane Shift becomes a Finalized Chain Item on the stack.
2. Banish Fizz: As Arcane Shift begins resolving, Fizz is moved from the board to the Banishment zone.
3. Play Fizz: Arcane Shift instructs you to play the banished unit. Fizz moves from Banishment back to a battlefield.
   • Per Rule 356.2, units leave the chain and become game objects immediately. They do not stay on the chain and cannot be reacted to.
4. Fizz Triggers (WYPM): The moment Fizz is played, his "When you play me..." ability triggers. This ability is added to the chain as a Pending Item on top of the still-resolving Arcane Shift.
5. Deal Damage: Arcane Shift continues its resolution, dealing 3 damage to the targeted enemy unit.
6. Arcane Shift Banishes: The final instruction of Arcane Shift is to banish itself. It moves from the chain to the Banishment zone.
7. Fizz Ability Resolves: Now that Arcane Shift has finished resolving and left the chain, Fizz’s WYPM ability is the newest item on the chain. You now choose a spell in your trash to play.

Key Timing and Interaction Nuances:

• Targeting Arcane Shift: You cannot use Fizz’s WYPM ability to play the Arcane Shift you just cast. Fizz’s ability requires you to "play a spell from your trash." Because Arcane Shift banishes itself as part of its resolution (Step 6), it never enters the trash. Even if it did, Fizz's ability targets upon resolution, and by the time you reach Step 7, Arcane Shift is already in the Banishment zone.
• LIFO and Triggers: While Fizz's trigger is added to the chain in Step 4, it cannot begin its own resolution until the current item (Arcane Shift) finishes all its text. This is why the damage and self-banishing happen before you actually pick a spell with Fizz.
• Showdown Timing: If this occurs during a Showdown, Fizz’s WYPM ability is a triggered ability that uses [REACTION] timing. It is added to the chain even while the state is CLOSED. Once the chain (including Fizz's ability) fully resolves and the chain is empty, the state becomes OPEN, and focus returns to the player who currently has it to start a new chain or pass.