Shandalar - Program Bugs

[Korath]

This is definitely different than Man-o'-War, yes. I guess there's no chance that the Doppelganger was Sleighted, or your Nekrataal laced? (When I tested this, neither I nor the AI were able to use the copied Nekrataal's etb trigger, so there's something weird going on somewhere.)

I see that the Doppelganger's incorrectly copying the Nekrataal's color, too.

Try to test with AI having a legal target for the copied Nekrataal to begin with like I had Old Man of the Sea then maybe the bug will appear.

[Korath]

Good call. What's happening is that the Vesuvan Doppelganger isn't clearing the creature it's copying out of its targets[0]; so when Nekrataal's - or anything else's - enter-the-battlefield trigger, or likely any targeted trigger or activated ability, runs, it selects and validates the correct target into targets[1], and then executes its effect on targets[0].

[Korath]

This is also the cause of the problem with copying Aven Cloudchaser reported here, which I overlooked when I saw the "original type" menu bug in the same report (now #554).