Rule 712.21c

If an effect can find the new object that a melded permanent becomes as it leaves the battlefield, it finds both cards. (See rule 400.7.) If that effect causes actions to be taken upon those cards, the same actions are taken upon each of them. Example: Otherworldly Journey is an instant that reads “Exile target creature. At the beginning of the next end step, return that card to the battlefield under its owner’s control with a +1/+1 counter on it.” A player casts Otherworldly Journey targeting Chittering Host, a melded permanent. Chittering Host is exiled. At the beginning of the next end step, Midnight Scavengers and Graf Rats are both returned to the battlefield, each with a +1/+1 counter on it. Example: False Demise is an Aura with the ability “When enchanted creature dies, return that card to the battlefield under your control.” A Chittering Host enchanted by False Demise dies. The triggered ability returns both Midnight Scavengers and Graf Rats to the battlefield. Example: Mimic Vat is an artifact that reads, in part, “Whenever a nontoken creature dies, you may exile that card.” A Chittering Host dies. As Mimic Vat’s triggered ability resolves, its controller makes a single choice and both cards that represented Chittering Host are either exiled or not.