collosus (here you go David)

immutuable form. the collosus is immune to effect that would alter it's form.

rage. when the collosus goes below half hp it goes into a frenzy, while in that state it only takes half damage and gets +4 to his attacks.

forever servants. the collosus will always be loyal to the one which created it and will do every command his masters tell him. the colosus is the same alignement as his master.

flammable oil. if the collosus would take fire damage he instead takes no damage and the oil on his tentacles ignites. his tantacle attacks will then do fire instead of acid damage for 1 minute.

multiattack. the colosus makes 4 tentacle attacks

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: (4d6 + 6) bludgeoning damage. 

tentacles. meele Weapon Attack: +5 to hit, reach 15 ft., 1 target. Hit: (2d4 + 6) piercing damage and the target needs to succeed on a DC 15 con. save taking 3d6 acid damage on a failed save and half as much on a successful one.