Skeletal Wyverns are found in the Asgarnian Ice Dungeon and the Wyvern Cave. They are undead creatures, making them immune to poison and venom. These fearsome foes require level 72 Slayer to be assigned as a task, and they drop various valuable items, known for being a good task in terms of consistent gp and profit, aside from buying OSRS gold making them a popular choice for high-level players.
There is currently only one location you can kill Skeletal Wyverns. They are located in the Asgarnian Ice Dungeon.