Skrelv can be tapped to give any creature you control toxic 1, unblockable, and hexproof from any one color until end of turn
This can easily be a five-mana Craterhoof Behemoth-esque effect for kindred decks that are not in green, even if they are in green, this is still a solid anthem effect
And, even if the opponent isnt completely wiped out right away, its a source of continuous damage
Even Brainstorm - notoriously strong card - wouldn't become good until fetch lands and shuffle effects would become more prevalent
MTG would waffle back and forth on "dog" versus "hound" as the creature type to call these domesticated canines
And if you happen to have access to the original dual lands ( Dang, look at you, baller