What happens when you put Temporary on a unit with GA or Zhonya?

When a unit has the Temporary keyword and is protected by Zhonya's Hourglass or Guardian Angel, the interaction follows the rules for Replacement Effects (Rule 369/370).

Here is the breakdown of how these interactions function:

1. Interaction with Zhonya’s Hourglass

When a unit with Temporary triggers at the start of your Beginning Phase, it attempts to kill the unit (Rule 816.1.b). Zhonya's Hourglass acts as a replacement effect that intercedes during that "die" event (Rule 369.1).

• Result: The unit survives the current turn. The replacement effect "replaces" the death with healing, exhausting, and recalling the unit to your base (Rule 369.1, FAQ #8940).
• Persistent Status: The unit retains the Temporary keyword even after being saved (FAQ #8940).
• Subsequent Turns: Because the unit still has the Temporary keyword, the effect will trigger again at the start of the next turn's Beginning Phase, and the unit will attempt to die again (FAQ #8940, FAQ #301).

2. Interaction with Guardian Angel

Guardian Angel functions similarly as a replacement effect, but it is attached to a specific unit (unlike Zhonya's, which can protect any friendly unit).

• Result: If the unit with Temporary would die, the effect is replaced by the destruction of the Guardian Angel instead. The unit is healed, exhausted, and recalled to your base (Rule 369.1).
• Persistent Status: Similar to the Zhonya's interaction, the Temporary status remains on the unit.
• Subsequent Turns: Since the unit still has the Temporary keyword, it will continue to trigger at the start of your future Beginning Phases. Unless another effect saves it, it will die the next time the Temporary trigger occurs (FAQ #301).

Key Ruling Summary

• Temporary is a trigger: It triggers at the start of each Beginning Phase. Saving the unit from one instance does not remove the keyword from the unit (Rule 816, FAQ #301).
• Replacement Effects take precedence: Zhonya's and Guardian Angel successfully "replace" the death, but they do not clear the "Temporary" status (Rule 370).
• One attempt per phase: The Temporary trigger occurs once per Beginning Phase. If you save the unit, it will not attempt to die again until the start of the following turn (FAQ #5544).

This interpretation is based on Rule 369/370 (Replacement Effects), Rule 816 (Temporary), and FAQ #8940, #5544, and #301.