Skull Storm Strategies
Beefing up the Power of a Wolf seems like a good alternative to Mantis God. Essentially get a creature with at least 5 Power, or 4 Power if supplemented by other things like Alpha or Mantis or Mantis God, use the removal Item, and then hit the opponent where it hurts (in the space that is now missing a Grizzly).
You pretty much need to win in one turn once the wall of Grizzlies shows up, at least most of the time. In any case, showing off usually isn’t worth it because the Grizzlies shouldn’t be underestimated. Flying creatures can help supplement damage if Magickal Bleach is used, but unless you are specializing in a Flying deck then you shan’t be able to generate enough damage without also using a removal Item.
If you have more than one removal item than you can combine the Power of yet another creature on top of the primary attacker, but this may be occasionally tricky because of the randomness of Item generation.
The most important thing is to ensure that you have the items you need prior to getting to the Grizzly Boss phase. That usually means carrying around Pack Rats in the deck and cycling through Items to get the ones that are effective against the wall of Grizzlies (Scissors, Knife, Wiseclock, occasionally Magickal Bleach if one has a deck with high-powered Flying creatures, etc.).
The more cycling through Items you do, the more likely you are to get multiple useful Items in reserve. (And of course you should try to avoid using Items that you are going to need for the Grizzlies later.) It’s also important to set up during phase 1 of a boss battle (including cycling through Items using Pack Rats if you don’t already have the Items you need for the Grizzlies) so that one is ready for the Grizzlies during phase 2.