Quite impressive. If I wasn't so up-to-date on my mental card catalog, I would've mistaken this for official card art!
Btw, is the victim supposed to be anyone in particular? My first thought was one of the other planeswalkers, but it doesn't resemble Garruk enough and Tezzeret has a glowing etherium arm. My second guess is Kresh, the Bloodbraided (or some random Alaran barbarian).