The staff is just an ordinary staff, but the vine wrapped around it is a Wood Spirit.
Previously, Angel had kept the Wood Spirit with him, but later he stored it away to enter the Mirror Domain. However, the Wood Spirit didn't want to stay in the bracelet because Dangross was inside.
Angel thought about it and simply let the Wood Spirit sink into the shadow with Earl Mi.
It's not that the Wood Spirit isn't afraid of Earl Mi, it's purely that it had to choose the lesser of two evils. It fears Dangross, it fears Earl Mi, but it's not afraid of the Blue Lantern Flower on Earl Mi's head, it even feels close to it.
The Wood Spirit cannot discern that the Blue Lantern Flower is actually Earl Mi; it only feels that the Blue Lantern Flower is filled with a familiar aura, and staying around it gives it a sense of safety, as if... it has reached a safe harbor.
