Where can it be found

Brimhaven Dungeon

Tactic

Melee or Mage is strongly recommended here. Protect prayers are also advised unless an extremely high level. Using fire bolt is quite effective on them. Also, ranging them with a Rune crossbow with enchanted Ruby bolts or better is extremely effective.

Examine Message

Its scales seem to be made of iron.

Notes

Anti Fire Breath potions and shield are a must.