Laser Beams/Doors of doom open.: Damages your party for about 400 physical damage.
Crystal Explosion: Damages your party for about 100-300 fire damage.
Obstacle: Damages your party for about 100-200 lightning damage, chance to inflict Chaos status no matter what.
Shadow Slay: Damages your party for about 50-100 damage, chance to inflict Poison status no matter what.
Flame Battle: Damages one ally for about 50-100 fire damage.
Shadow Doom Blaze: Damages your party for about 100-400 fire damage.
Curse: Removes Status Immunity.
Lavos’s Final Form
2,000 (Left Bit), 10,000 (Lavos), and 30,000 (Right Bit)
Interestingly, trigger abilities such as Lavos core shuts off defense, Lavos core defense restored! and Time warp… can all be counterattacked by Rage Band or Frenzy Band’s effect despite dealing no damage to anything.
Attack: damages one ally for about 100 damage.
Heal: heals Lavos for 1000HP.
Drain MP: steals about 10 MP from one ally and gives it to itself.
Protective Seal: Voids status immunity.
Attack / Will attack with no center bit: a counter attack if you’ve destroyed the center bit.
Central Bit (body/decoy)
Punch: damages one ally for 200-999 damage
Crying Heavens/Hidden blow: damages one ally for about 200-1600 lightning damage depending on resistance modifiers, magic defense and which character it is. If the character is wearing a White Vest/Mail, it will heal instead!
Time warp…: changes the time period, which changes the background of the fight and is used to determine the super attack used (see below). If you have either the Rage Band or Frenzy Band equipped, you can counter this pseudo-attack.
Spell/Random Status (Leene Square 1000 AD): attacks one ally for 150-300 damage and attempts to inflict a random status ailment.
Evil Star/Reduces HP by 1/2 (Magus’s Castle 600 AD): reduces each ally’s HP by 1/2.
Dreamless/Ultimate Magic attack (Lab Ruins 2300 AD): deals 100-500 magic damage to your party.
Invading Light/Slow (Mammon Machine 12000 BC): damages the party for 100-200 damage and attempts to inflict Slow.
Grand Stone/Ultimate phys. attack (Hunting Range 65,000,000 BC): damages the party for about 250-950 physical damage.
Right Bit (core)
Prisma Drain: damages one ally for about 100 damage.
Lavos Core shuts of def: removes both physical and magical defense. If you have either the Rage Band or Frenzy Band equipped, you can counter this pseudo-attack.
The Lavos Core’s Def pwr restored!: the Right Bit’s physical and magic defense increases to the maximum. If you have either the Rage Band or Frenzy Band equipped, you can counter this pseudo-attack.
About Challenging Lavos
If you challenge Lavos during this chapter, you should get The Main Ending, although you are able to reach this chapter without Crono as well, in which case you would get The Reunion Ending. There are several variations depending on whether or not you crashed the Epoch into Lavos, spared Magus, and a few minor ones depending on how you completed Fiona's sidequest, and how many cats you have. The basic theme of the ending is that Crono and company get honored for their work in saving the past, and have a farewell party. You should also have activated the New Game+ by finishing the game in this chapter, so you can now restart your game with ridiculously powerful characters and try for some of the other endings.
Another “Lavos” Ending
If you lose to Magus in the battle against him in his castle, he will turn around and raise his arms, and you will begin to hear Lavos make his trademark "scream". It can probably be inferred from this, and from comments that Magus makes later in the game, that Magus was in the process of summoning Lavos to his castle where he failed at defeating him.
Another side note, these two battles are the only known ones that trigger special endings, although you can also lose the first battle against the Golem which will similarly lead to you getting trapped by Zeal.
This is all about CHRONO TRIGGER – The Final Battle/Strategy To Beat Lavos; I hope you enjoy reading the Guide! If you feel like we should add more information or we forget/mistake, please let us know via commenting below, and thanks! See you soon!