Okay, so I use this forum all the time for answering those strange questions that come up during deck construction. I couldn't find an answer to my question however, and I don't know how to card link. Sorry about that.
The question is: if renegade doppelganger copies a card such as artisan of forms, then becomes targeted, will it remain as the new copy (of the heroic ability target), or will the delayed end of turn trigger undo this otherwise beautiful combo?
When Renegade Doppelganger becomes a copy of a permanent, it acquires that permanent's copiable values (C.R. 706.2), so that, for example, if it becomes a copy of Artisan of Forms, it becomes a copy of whatever Artisan of Forms currently is (in terms of its copiable values). Renegade Doppelganger's copy effect (which lasts only "until end of turn" — there's no delayed triggered ability involved [C.R. 611.2a; review C.R. 603.7]) is independent of how long that of Artisan of Forms lasts (which lasts indefinitely since it has no duration [C.R. 611.2a]) (see also this thread).
If Renegade Doppelganger then becomes a copy of yet another creature using the ability it acquired from Artisan of Forms, that creature's copiable values will overwrite Renegade Doppelganger's existing copiable values indefinitely, regardless of how long any other copy effect then on Renegade Doppelganger lasts, since the latest effect wins in this case (C.R. 613.6, 613.7, 611.2a, 706.2, 706.3).
The question is: if renegade doppelganger copies a card such as artisan of forms, then becomes targeted, will it remain as the new copy (of the heroic ability target), or will the delayed end of turn trigger undo this otherwise beautiful combo?
Thank you for your time.
If Renegade Doppelganger then becomes a copy of yet another creature using the ability it acquired from Artisan of Forms, that creature's copiable values will overwrite Renegade Doppelganger's existing copiable values indefinitely, regardless of how long any other copy effect then on Renegade Doppelganger lasts, since the latest effect wins in this case (C.R. 613.6, 613.7, 611.2a, 706.2, 706.3).