Hemoshift

7th-level conjuration (hemomancy)
Casting Time: 1 hour
Range: Touch
Components: V, S, M (ornate vials worth at least 50 gp each)
Duration: Instantaneous

While casting the spell, you touch and imbue up to eight vials containing the blood of creatures with powerful conjuration magic, in an intricate ritual. After you finish casting the spell, the imbued vials become magical objects, retaining their magical properties for one month, after which they become nonmagical.
While holding an imbued vial, you can use an action to expend the residual magic in it. When you do, you are immediately transported to an unoccupied space within 5 feet of the creature whose blood the vial contains, even if the creature is on a different plane of existence. After you transport, the vial loses its potency and becomes nonmagical.

Alternatively, while holding an imbued vial, you can use an action to expend the residual magic in it to summon the creature whose blood the vial contains in an unoccupied space within 5 feet of you. If the creature is unwilling, it can make a Charisma saving throw to resist the spell's effects. Whether the creature is successfully transported or not, the vial loses its potency and becomes nonmagical.

Amplify X. The vials retain their potency for an amount of months equal to X, instead of one month.