Undertale Boss Battles Script

Writing a script for Undertale style battles is notoriously buggy. Here is the debug checklist every creator needs:

| Boss | Gimmick | Script requirement | |------|---------|--------------------| | Toriel | Attacks avoid you if low HP | Check player HP and aim away | | Papyrus | Captures you at low HP, then spares | Interrupt attack phase if HP < 3 | | Sans | Karma (KR) poison damage | DoT effect that ignores i-frames | | Mettaton | Rating system (ratings affect defense) | Count “spectacular” dodges | | Asgore | Destroys MERCY button | Disable MERCY UI element mid-fight | Undertale Boss Battles Script

function fight() 
  let baseDamage = 10 + (player.lv * 4);
  let defenseFactor = boss.defense / 10;
  let damage = Math.floor(baseDamage / defenseFactor);
// Random variation ±2
damage += Math.floor(Math.random() * 5) - 2;
boss.hp -= Math.max(1, damage);
showText(* You attack. $damage damage.); Writing a script for Undertale style battles is
// Sans special: if you attack, he dodges.
if (boss.name === "Sans") damage = 0;