I know that if I activate the Monstrosity ability of
Nessian Asp and as a reaction to that ability, make it a copy of
Polukranos, World Eater (probably either via
Polymorphous Rush or
Artisan of Forms), I do get the 4 +1/+1 counters from the ability resolving but Polukranos's triggered ability does nothing because it does not see a value chosen for X.
But what if instead of Nessian Asp it was
Hydra Broodmaster, which also has Monstrosity X? Does the X carry over to the copy, or is it like linked abilities and Polukranos's triggered ability does not recognize the X paid for Hydra Broodmaster's Monstrosity ability?
I do realize that because the Monstrosity costs are the same, there is usually very little reason to do this. I can construct a Limited scenario where it is plausibly the correct play, however, if there are people who care about that. The scenario is not exactly likely (it does involve two rares and one mythics controlled by the same player), but it is not impossible that such a thing happens in a Limited game, especially since there are probably other situations I did not think of:
Nymeria controls Bronze Sable and a tapped Pharika's Chosen. Arya is at 3 life and controls an un-monstruous Polukranos and a tapped Hydra Broodmaster enchanted with Eternity Snare, with Polymorphous Rush in hand and 6 total available mana. Arya activate Polukranos's ability for X = 1, in the hope to remove the blocker, then attack with it. As a reaction Nymeria plays Pharika's Cure on her own Bronze Sable, which would force Arya to have Polukranos “fight” Pharika's Chosen and die. To avoid losing Polukranos, Arya makes it into a copy of Hydra Broodmaster before its Monstrosity ability resolves.
Edited Nathanaël François (April 28, 2014 11:41:20 AM)