Rule 707.11

If an effect refers to a permanent by name, the effect still tracks that permanent even if it changes names or becomes a copy of something else. Example: An Unstable Shapeshifter copies a Crazed Armodon. Crazed Armodon reads, “{G}: Crazed Armodon gets +3/+0 and gains trample until end of turn. Destroy Crazed Armodon at the beginning of the next end step. Activate only once each turn.” If this ability of the Shapeshifter is activated, the Shapeshifter will be destroyed at the beginning of the next end step, even if it’s no longer a copy of Crazed Armodon at that time.

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