Lalli is a troll cook that guards the Golden Apple Tree. He is needed in The Fremennik Trials to get the Golden wool required to make the lyre. After the quest, the golden fleece can be bought for 1000 coins each from him. He seems to be constantly paranoid that you are going to steal his golden apples. Lalli is the only known troll cook who does not eat humans. He is fooled by you and a pet rock during this quest.
He can be reached quickly by using the fairy ring AJR to get to the Rellekka Slayer Caves. Slower methods include using the enchanted lyre to teleport to the Rellekka area, by teleporting to a player owned house (if set to Rellekka).