The big downside with Grim Giganotosaurus is that it doesnt have a built-in trample effect, making it susceptible to being blocked by little 1/1s all day long
The four main rarities are Common, Uncommon, Rare, and Mythic Rare
Path to Exile is the optimal removal for the deck (especially since we can sometimes eliminate the downside of giving our opponent a land with Leonin Arbiter), but Declaration in Stone is a fine budget replacement with some upside against token decks since it exiles all copies of a creature
10 Vile Mutilator An Awful Way To Go Yes, seven mana is a lot to pay for a 6/5 flying trample, especially one that requires either an enchantment or creature sacrifice
Which is great, because this is far too fun of a scene to be hard to collect
If your opponent has an extremely high-cost deck, it may be worth searching for "OP04-044 Kaido" or a Character with a +2000 [Counter] instead