Staff of Athreos

Staff, legendary (requires attunement by a worshiper of a god of death)

Price: 100,000-200,000 gp | high sentimentality

This gnarled staff belongs to devotees of Athreos, the god of passage, who ferries souls across the rivers separating the Underworld from the mortal realm. With the staff in hand, you can use an action to dip the base of the staff into water to transform the staff into a boat capable of carrying yourself and 6 creatures of Medium size. When the staff transforms, its upper half forms the prow of the boat and you must maintain your grip on the prow to keep the staff transformed. When the staff first transforms into the boat, you raise your maximum hit points by 100 and gain 100 hit points. When the boat transforms back into the staff, you lower your maximum hit points by 100 and lose any hit points you have over your new maximum. You suffer all damage suffered by the boat or occupants of the boat. The boat has a speed of 60 feet. You can let go of the prow or use an action while holding the prow to transform the boat back into the staff. The boat transforms back into the staff if you fall unconscious.

Paid

While the staff is transformed into a boat, you gain resistance to all damage types and creatures can’t make attacks of opportunity against you, your boat, or anyone in your boat. The boat can’t capsize and occupants of the boat have advantage on saving throws against effects that would knock them out of the boat. You have advantage on attack rolls when an enemy is within 5 feet of your boat.

Overpaid

Once a day for the first ten days after you attune to the staff, you may cast the commune spell without requiring material components to contact Athreos.

Source: The Gray Merchant of Asphodel