Final answer:
The verbal phrase in the given sentence is 'had disappeared entirely,' indicating a completed action.
Step-by-step explanation:
The phrase in the sentence "The feet of the dead witch had disappeared entirely, and nothing was left but the silver shoes" that is a verbal phrase is had disappeared entirely. A verbal phrase consists of a verb form that functions as something else in the sentence, such as an adjective or a noun, which in this case is part of the verb phrase indicating a completed action.