We might disregard the card because it looks like a one-for-one, but then we realize its not, since it replaces itself
Luckily, winning the game with Hive Mind in play is generally quite simple
When the evoke elementals were spoiled in Modern Horizons 2, people waxed lyrical about how broken Grief with Ephemerate was going to be, but in practice that interaction did not make any material impact on the format, and instead its been more commonly combined with Fury and Solitude in the Four-Colour Yorion, Sky Nomad decks
All in all, milling your opponent out isnt a particularly great strategy, and lets face it: there are much better cards youd want to play than Trepanation Blade
In theory
Youll win by copying a bunch of combat tricks like Infuriate or Monstrous Rage across a wide board