Metal Allegiance, the metal supergroup featuring core members David Ellefson (Megadeth), Alex Skolnick (Testament) and Mike Portnoy (The Winery Dogs, ex-Dream Theater), along with multiple special guests, have posted a new webisode for their song “Triangulum” featuring Misha Mansoor (Periphery), Phil Demmel (Machine Head), Ben Weinman (The Dillinger Escape Plan), Matt Heafy (Trivium), Ron “Bumblefoot”…