I present from the SuperJoe files; GOR!
GOR; King of the Terrons
AC 17, HD 5d6, THB +5, ATT claw 1d6/claw 1d6/bite 1d6 or Destructo Ray 2d6, ST 14+, MV 6, XP 600
Special Abilities: Thick Scaly hide, Destructo Ray (cone attack, range 6 m, 2m wide, agility save or all in cone suffer 2d6 damage; must recharge after use i.e. Gor must roll a 6 on a d6 to use this attack again in the same encounter), Regeneration (1d3 every turn), Dark Vision
Weaknesses: Glass Jaw; if his opponent is skilled in martial arts and rolls an 18-20 via an unarmed attack Gor has been hit in the jaw and is knocked out for 1d6 rounds.
Gor, this savage reptilian alien is a terror to all he encounters! Nearly three meters tall, covered in thick green scales, he loves to unleash his Destructo Ray on the unwary! Gor will initiate an attack using his Destructo Ray, trying to catch as many of his foes as possible with this attack then he will charge into melee using a vicious claw/claw/bite attack, relying on his regenerative abilities to keep him in the fight, as soon as possible he will unleash another blast of his Destructo Ray. While savage and cruel he is no fool, if he is seriously injured and/or losing the fight he will retreat only to heal up, charge up and start the fight again, sooner rather than later.
I wrote him up for X-plorers but he can be used with all sorts of Old School games, for Mutant Future I'd up his hit points to allow for that systems higher HD ratio. Good Gaming -B.