Slime Separation

You can spend 1d4 hit points to detach a small portion of your body to serve a purpose as a bonus action or reaction. The portion of you that is separated cannot swap functions. The separated portion of you has 1d4 hit points subtracted from your own hit point maximum upon the moment of separation. This can only be regained after rejoining with you, or being destroyed, after which you can regain that hp via a long rest. This ability is susceptible to effects that block magic such as an anti-magic field or zone. You can do this once per long rest. you can only do this as a reaction to an attack if that attack does only slicing damage and isn't a critical hit. If you do, negate the damage slashing damage the attack would have done. The portion of your being that becomes separated from you can be utilized via the following abilities:

Slime Familiar: You can create a slime familiar that behaves and with the same features as one summoned via a find familiar spell would. It is considered a tiny creature with a walking speed of 30 feet,  and has the spiderclimb ability. It doesn't need to breath and Its hit points are equal to the number of hit points you spent to create it and you may regain those hit points by re-absorbing the familiar as your own or it's own action. It shares the same perception and passive perception as you as well as the same bonuses to athletics, acrobatics and stealth. It has a acid attack that does 1 acid damage. In addition, its telepathic range and the distance from it which you can be to see through it is extended up to 300 feet, but any further and the familiar becomes an inactive puddle of goo that cannot make any actions, move or provide any benefit until you are once again within range. If you are out of range with your slime familiar for more than 1 hour, it ceases to be a familiar and you do not regain the hp you spent to create it until you take a long or short rest or as the result of another healing effect or spell. If your hp ever reaches 0, your familiar will stop any activity it is currently doing and will spend all its action and movement with the purpose of returning to you to be re-absorbed as its action.

Slime's Mark: You choose a creature you can see within melee range and mark it. Until the ability ends, you deal an extra 1d6 damage to the target whenever you hit it with a weapon attack, and you have advantage on any Wisdom (Perception) or Wisdom (Survival) check you make to find it unless it is within 100 feet of you, in which case you know its exact location. If the target drops to 0 hit points your mark is dismissed.  If you wish for the mark to go unnoticed, roll a stealth check. The marked creature can recognized it has been marked with a passive or active perception check equal to or higher than your stealth check.

Note: You must be a Half-Slime to use this feat