Phyrexian Metamorph/Blightsteel Colossus/Viashino Heretic

[Meddling Mike]

This one came up in the most recent TMD Online Invitational.

Onslaught Controls a Blightsteel Colossus and a Viashino Heretic.

Nataz plays a Phyrexian Metamorph targeting Blightsteel Colossus.

Onslaught activates Viashino Heretic's ability targetting the Phyrexian Metamorph that is copying the Blightsteel Colossus.

In this scenario Nataz put the Metamorph into the graveyard and took 4 damage. Is this what should happen?

[H]

No, not at all.

First, Phyrexian Metamorph does not target, it enters the battlefield as a copy of your choice (this distinction is important for copying anything that has hexproof, shroud or any other targeting restrictions).

Second, once the Metamorph is on the battlefield and can be targeted by the Heretic's ability, he is a copy Blightsteel Colossus in all ways, shapes, and forms.

Due to this, what should have happened is that Heretic's ability should deal 12 damage to Nataz and that is all. The copied Blightsteel is indestructible but dealing the damage is not contingent on Heretic's target being destroyed.  He would take 12 because when copying something, every aspect of that card is copied including it's CMC (which is what Heretic's oracle text refers to the amount of damage dealt being).