Guardian

 is a boss in. Found in the Arris Dome when Crono, Lucca, and Marle flee to the Future prior to Crono's incarceration, the Guardian protects the food storage area beneath the Arris Dome. The player must defeat it to bring food to the hungry people in the levels above. Clicking on the rat "statue" outside the food storage area allows the player to read a memo attached to it, which warns them of the fight against the Guardian.

Battle and Strategy
For this fight, focus all attacks on the Bits first, then the Guardian, once the Bits have been defeated. Heal periodically using Aura with Marle, or the dual tech Aura Whirl in desperate situations. After the Guardian counts down to 0 from 5, the Bits will reanimate. Always attack them first and destroy. Attacking the Guardian while the Bits remain active causes them to counter with a strong tech. After destroying the Bits, quickly attack the Guardian with each character's regular physical attacks. Using Fire Whirl or Flamethrower is useless due to the Guardian's immunity to Fire. Techs such as Cyclone and Wind Slash do approximately as much damage as physical attacks, so it is advised to save the Magic Points and attack with Swords and Guns.

Because the Guardian really doesn't have that much HP, it should be defeated after 2-3 rounds of the strategy outlined above (assuming one isn't going for a low level run).

Lavos
When the players fight Lavos, it will have the same strength as the bosses you've faced in the past. One of them is Guardian (with Pods).