The Old Bone is three ingredients on Shark Tooth Island for making a sleeping potion for the Booga. You will need this sleeping potion to rescue Professor Hammerhead and a young boy who have been trapped on an island in Booga Bay which is your mission in this Island.
Where to Find the Old Bone
All three ingredients are easy to find, down in the underground chambers in the Ancient Ruins, you can easily find the Old bone. Once you got all three ingredients hand them to the Medicine Man to make the Sleeping Potion.