Clone

8th-Level Necromancy
Casting Time: 1 hour
Range: Touch
Components: VSM($) (a diamond worth at least 1,000 gp, which the spell consumes, and a vessel worth at least 2,000 gp that has a sealable lid and is large enough to hold the creature being cloned, such as a huge urn, coffin, mud-filled cyst in the ground, or crystal container filled with salt water)
Duration: Instantaneous

You touch a creature or at least 1 cubic inch of its flesh. An inert duplicate of that creature forms inside the vessel used in the spell’s casting and finishes growing after 120 days; you choose whether the finished clone is the same age as the creature or younger. The clone remains inert and endures indefinitely while its vessel remains undisturbed.

If the original creature dies after the clone finishes forming, the creature’s soul transfers to the clone if the soul is free and willing to return. The clone is physically identical to the original and has the same personality, memories, and abilities, but none of the original’s equipment. The creature’s original remains, if any, become inert and can’t be revived, since the creature’s soul is elsewhere.

At Higher Levels. When you cast this spell using a spell slot of 9th level or higher, the time it takes the clone to reach maturity is reduced by 30 days for each slot level above 8th.

Source: PHB 222, SRD

Changelog

Added upcasting option.
Clarified that the inch of flesh is an alternative to touching the creature.