The Amorphous Parasites

Ability Scores and Traits

Ability Score Increase. As a Symbiote you increase your Charisma by 1.
Age. Symbiotes are born of magic and dead oozes, created fully sentient and aware, they live to be a few hundred years old before they can no longer survive, even with a host body.
Alignment. Symbiotes usually strive for freedom in life and as such most of them are Chaotic. They are also required to have a moral flexibility to survive so they're either Neutral or Evil most of the time.
Size. While in your usual form your size is medium and you are a ball of slime and ooze, however when inside your hosts body you adopt their size.
Speed. Your movement speed is 15ft while in your true form however you can move through spaces only a few inches in diameter without squeezing. While you are in your hosts body however you have their speed +5ft.
Darkvision. You can see in dim light within 60 feet of you as if it were bright light, and in Darkness as if it were dim light. You can’t discern color in Darkness, only shades of gray.
Amorphous. You are an amorphous blob of slime and ooze of all sorts of colors while not in a host, you cannot wear anything or use any object or weapon while in that state, nor can you speak. You can attempt to take over a hosts body during a period when the host is taking a long rest. To do so make a Strength (Athletics) check against their Strength (Athletics) or Dexterity (Acrobatics) check to latch onto them and overcome their natural reactions to you attempt to force yourself into one of their orifices. If you succeed you can attempt to take over your hosts brain by rolling a Charisma (Persuasion), Charisma (Deception) or Charisma (Intimidation) check against their Wisdom Saving Throw. If you fail either of these attempts however, you land within 5ft of your host (DM's choice) and cannot attempt to take over the same host for 24 hours.

Host Body Control. After succeeding to take over both your hosts body and brain you are counted as the same singular creature. You adopt all the Ability Scores, Proficiencies, Class Levels, Feats and Traits etc. of your symbiote and your hosts body serves only as a disguise for your true form. After taking over your hosts body you can use their voice to communicate with others, and they are completely under your control. They cannot speak, control any part of their body or mind, but they retain all memory of the events that transpire while you are controlling them.
Emergence. You have the ability to emerge from your host body as a Bonus Action, covering it completely in your slimy oozoid form and giving boosting it's capabilities for a limited amount of time. The effects of this ability are affected by your subrace and last for 1 minute. You can end this ability early as a Bonus Action. You regain the use of this ability after a Long Rest.
Languages. You can speak Common and Primordial.

Venom

Venom Symbiotes are large and bulky. They like to find extremely strong individuals to be their hosts.

Ability Score Increase. Your Strength Score increases by 2.
Natural Fright. You are proficient in the Intimidation Skill.
Muscle Emergence. You cover your hosts body with your true form, giving it a fluid slimy and muscular appearance. Your size increases by one degree (Small to Medium, Medium to Large, etc.). Everyone that can see you when you transform must make a Wisdom Saving Throw against a DC of 14 or be frightened of you until the end of your next turn. All your Strength based attacks gain a +3 to Damage Rolls as long as you are transformed.

Tendril Attack

To Hit: d20 + Your Dexterity Modifier + Your Proficiency Bonus
Damage: 1d6 Piercing Damage