The Stitcher

The stitcher is a wizard subclass focused on the use of medicine in combination with magic to work miracles and horrors. Often their ultimate ambitions are to defeat Death or to create Life. 

Extract Essence

At 2nd level, you have a deep understanding of the way organic being work and can extract useful components from them. You gain proficiency with the Medicine skill. In addition, you can spend an hour dissecting the corpse of any Beast, Aberration or Monstrosity to extract consumable ichors with one of the following properties:

• gain one damage resistance/immunity of the source creature for 1 hour
• gain one condition immunity of the source creature for 1 hour
• gain a single use of one of the source creature's special abilities (e.g. an Ankheg's acid spray) which must be used as an action within 1 hour of consuming the ichor. 
• gain one of the creature's senses for 1 hour

These ichors lose their potency within 1 hour unless they are stored properly each which case they last 1 week. Once you have extracted a batch of ichors from a corpse no further ichors can be extracted. The corpse must be in a reasonable state to have ichor extracted from it. 
Every time you use this ability you gain a number of ichors equal to your proficiency bonus. 

Arcane Graft

Beginning when you select this school at 2nd level, you learn to alter your or an ally's physical form with eldritch chirurgery. Over the course of a short rest, you can attach up to two body parts to a player. This could be reconnecting a part that had been severed, but you can also attach parts from a similarly-sized humanoid. The new part cannot have been separated from a living body for more than 24 hours. In the same amount of time, you can safely swap a currently attached body part for another. You can choose for the new limb's appearance to stay the same or to shift to match your own design.

Idle Hands

Starting at 2nd level, you learn how to release your hands from your body.
As a bonus action, you can spend 2 hit points to detach one of your hands and turn it into a Crawling Claw (MM, p.44). It is entirely under your control and takes its turn immediately after your own. When you cast a spell with a range of Touch you can deliver the spell through the crawling claw. The crawling claw becomes incapacitated whenever it is more than 1 mile away from you. When the crawling claw is within 5 feet of you, you can use a bonus action to reattach it. You can do so even if the crawling claw has been reduced to 0 hit points, and you regain hit points equal to the number of hit points it has remaining.

Idle Hands

As a bonus action, you can spend 2 hit points to detach one of your hands and turn it into a crawling claw (MM, p.44). It is entirely under your control and takes its turn immediately after your own. When you cast a spell with a range of Touch you can deliver the spell through the crawling claw. The crawling claw becomes incapacitated whenever it is more than 1 mile away from you. When the crawling claw is within 5 feet of you, you can use a bonus action to reattach it. You can do so even if the crawling claw has been reduced to 0 hit points, and you regain hit points equal to the number of hit points it has remaining.

Wandering Eyes

Starting at 6th level, you acquire the ability to send your eyes to do your bidding. As a bonus action, you can spend 2 hit points to detach one of your eyes and enchant it. When you do so, you cast the arcane eye spell using no components and without using a spell slot. Your eye itself takes on the properties of the spell. Should the spell end early, your eyeball becomes visible and drops where it is. When the eye is within 5 feet of you, you can use a bonus action to reattach it. If the eye is still intact, you regain the 2 lost hit points

Aberrant Form

When an attack against you is a critical hit, it is treated as a normal hit instead. Furthermore, when an effect refers to your race or creature type, you can choose to count as an aberration instead of your original type.

The Stitch of Life