Innate Spellcasting. Bone's innate spellcasting ability is Charisma (spell save DC 9). He can innately cast the following spells, requiring no spell slots:

Chattering Bones. Unlike a normal Skeleton, Bones is capable of talking. He is in fact. Seemingly incapable of not talking.   Cursed with Undeath. When bones drops to 0 hit points his spirit departs the skeleton form he is currently inhabiting, if there are any skeletons nearby he will inhabit their forms, gaining their current hit points and equipment but keeping his Intelligence, Wisdom and Chrisma stats, personality, spellcasting and legendary action. If their are no skeletons in the immediate area with 1 or more hit points his spirt will leave the area instead, adrift until he finds another skeleton to inhabit.