Bore only appears in the Stories of Legend and a few stages in Into the Future and Cats of the Cosmos. It has very high health, attack power, a very fast attack, and medium movement speed, like some kind of really powerful One Horn on steroids with more range. It is very hard to stall without status-effect spam. However, Pirate Cat, Witch Cat and iCat are able to ease the fight against it.
Always thought his name was the correct way to spell what he is. Turned really red after introducing himself. "I am a bore"
Always thought "boar meat" meant he was a lion* and turned red with embarrassment when a colleague corrected him. The roots are real.
* The joke relies on 'meat' and 'lion' being homophones in Japanese.
Strategy (For first encounter):
You will need AT LEAST three meatshields for the first time you encounter him.
When you first encounter it in Sea of Tuna on the 4th stage, summon in a meat shield of Wall Cat, Macho Cat and Samba Cat or Catburger, and any other cheap defensive cats you have. This should temporarily slow down the Gory and Kang Roo while you save up your money. Wait to reach Max money before sending out any expensive or strong cats, because as soon as the enemy base health is low enough, they will summon in the Bore. When you have Max money, summon in Bahamut Cat, Valkyrie Cat, and any other high damage AoE (Area Attack) units, like Paris Cat, for example, or any Anti-Red Cats that you have to knock him back, slow him, or stop the Bore. Both Pirate Cat and Hip Hop Cat work very well as Pirate Cat could repeatedly knock it back and Hip Hop Cat can deal massive chunks of damage and slow it down. When the Bore has been summoned, it should destroy most, if not all, of your front cats. Continue to use Wall Cat and Macho Cat to hold him back while Bahamut and Valkyrie Cat deal some heavy damage to him. If your Bahamut and Valkyrie Cat die, resort to using cats like Gang Cat and UFO Cat while they recharge. If this is done correctly, the Bore should die and you should be able to finish off the level.
Strategies for late-game encounter:
By now, you probably have more anti-reds, so a suitable strategy to easily wreck Bore would be to spam around 3 anti-red status-effect units and Island/Crazed Whale, along with your other units and meatshields. Ururun Wolf's fast attack speed and knockback chance also works well against Bore.
Able to kill easily, so a strong front line is necessary, up to three meat shield. Hold the front line while the other cats destroy it. The comforting part is that the red Bore usually appears as one of itself or with some support, making it easier to handle.
If you can spawn iCat in a way so that they alternate their attacks, you could perma-freeze the Bore while your heavy-hitters continually land strong hits on it.