Bright light creature

Bright Light Creatures can be found in the first floor of the Slayerdungeon of Priffdinas. They are the weakest monsters in this dungeon. They often drop air and cosmic runes. Their main use is to heal yourself at them, as you get 1 LP for each LP of damage you do to them. With the nearby altar, this is a great place to train at the Green dragons and the Baby green dragons inside, as you do not need any food nor prayer potions. Altough, for higher leveled player (100+), this may not of such a great use. The downside of them is, that for each 10th LP of damage you do, your prayer will drop for one point. Just recharge at the altar to get your prayer back. They also have a high defence level compared to their combat level, but shadow spells from the Ancient spellbook will almost always hit them. After The Princess and the Warrior Quest, they also drop Life runes, but that's rare.