Soulflies

Soulflies would be a mob similar in look to the Vex or Allay except closer to a firefly shape. They glow light blue and make amethyst-like crystally sounds as they fly around. They spontaneously appear near the player as they walk through biomes like the Forest, Dark Oak Forest, or Soul Sand Valley. After a certain amount of time, maybe 30-40 seconds, they fade away and dissipate. Right clicking them with an empty bottle fills it up with experience, giving you a Bottle o' Enchanting, and to make them easier to catch, they stay close to the ground and don't fly off into the sky.