Rule 712.21b

If a player exiles a melded permanent, that player determines the relative timestamp order of the two cards at that time. This is an exception to the procedure described in rule 613.7m. Example: Duplicant is a card with the abilities “When Duplicant enters, you may exile target nontoken creature” and “As long as a card exiled with Duplicant is a creature card, Duplicant has the power, toughness, and creature types of the last creature card exiled with Duplicant. It’s still a Shapeshifter.” As Duplicant’s first ability exiles Chittering Host, a melded permanent, Duplicant’s controller chooses whether the last creature card exiled is Midnight Scavengers or Graf Rats.