The key clause that makes it good (if it was an uncommon) is "you control." Yeah, I would have preferred it be an uncommon as a Sorcery, or rare and at Instant speed and bumped up to 4 mana for Insult
Now a Fighting type, in contrast to usually being a Metal type, this Zamazenta may not have huge HP, at 110, but it can be tricky for an opponent running a certain kind of Pokmon
Some internet speculation is Venture Into the Dungeon is a lesson like effect for dungeons that start in another zone, but if so I don't think it will be the side board, because otherwise this would make it useless in Commander and Brawl
Dont think that you need to spend too much mana on this X spell: Casting Meathook Massacre II on turn 4 is a game-changer
Those Commander decks will probably also be running Armageddon, which is functionally identical to Ravages of War, right down to casting cost and MTG color identity