text: function UpgradeDamageMultiplier(multiplier) {
    this.multiplier = multiplier;
  };
  
  UpgradeDamageMultiplier.prototype.onApply = function(laser) {
  
  };
  
  UpgradeDamageMultiplier.prototype.render = function(ctx) {
    //TODO: Not called, unsure how whether we need this and how it should be done.
  
  };
  
  UpgradeDamageMultiplier.prototype.update = function(laser) {
    //TODO: Not called. Unsure if we need it.
  };
  
  UpgradeDamageMultiplier.prototype.onEnemyHit = function(laser, enemy) {
    laser.nextDamage *= this.multiplier;
  };
  