Prowler (Mk. 2)

Prowlers drink a potion that allows them to take on a specific ability of a slain enemy by drinking their blood.

Vile Absorption

At 3rd level you drink a spoopy potion that lets you take on an ability of an enemy if you drink their blood at night(NOT DURING DAY).(Example: if you drink the blood of Phase spider you can choose to gain ethereal jaunt, spider climb or web walker[Why would you choose the last one?] also you can take passive abilities like a single damage resistance or immunity)
Limitations: Each morning you may choose any 5 of the abilities you have gained and can use any of them within the restrictions set by the stat blocks of the creature you got it from.
Also you have to make a medicine check to retrieve the blood the DM will have to decide the difficulty on the check
Finally, you may only take in one vial of blood each night.  I advise that you should have a sheet to take note of the abilities you have.

Drinking Habits

You can drink 2 or more vials of the blood of your enemies in one night but you have to succeed a DC 10 CON saving throw when drinking 2 vials (On 3 the saving throw is a DC of 14 on 4, 18 and so on) or throw up, losing the effects of all the blood you drank and roll a number of d4's equal to your level and take that much damage. Also you can prepare 1 extra ability a day.

Experienced Extractor

At 13th level you are now proficient in medicine checks (If you are already proficient in medicine checks you gain expertise if you already have expertise in medicine add your proficiency mod onto your expertise) and if you are no longer in combat when you attempt to extract blood from a dead (or unconscious) body you gain advantage on the roll. You get an extra prepared ability again.  

Playing Favorites

You have grown significantly in power and over your rise to greatness you have discovered 2 Prowler abilities that you are always able to use alongside the others that you prepare each day. You also get another Prowler ability that you can use each day. Once you reach 17 level you choose 2 Prowler abilities to always have prepared aside from the other 8, for a total of 10.