Venom symbiote PC

[Jeivar]

(Yes, really.)

I just got this nutty idea and starting working on fitting the basic idea into 5e. I'm leaving out the lore stuff, such as how they procreate, what their general mindset is and what they get up to. I just want some opinions on the mechanics. I think it might be fun to play a character with variable physical traits, but also made sure they can't just body-hop at will. It is also utterly dependent on having a host to survive and generally interact with the world. The idea is that the starting class is something they pick up from their very first host. Sort of like imprinting.

Symbiote
*Physical stats are all set at 4 each.
*Vulnerable to fire.
*Resistant to poison damage.
*Can use Spider Climb at will.

Alone:
*Has a movement speed of 15.
*Has advantage on Stealth rolls in low light conditions.
*Cannot carry items.
*For every 24 hours it goes without a host, the symbiote suffers one level of exhaustion.
*Slides around in ooze form, with a natural AC of 12.

A lone symbiote will seek out a suitable host, which must be of Small or Medium size. Upon making skin contact the target must make a Wisdom saving throw, whose difficulty is 8 + the symbiote's Wisdom modifier + its proficiency bonus. On a failure the host falls into a dreamlike state and the symbiote takes over as it fully covers the host's body.

The symbiote takes on the host's physical stats, although adding +4 to its Strength score, and +2 in Natural Armour. It gains access to none of the host's skills, Feats or class-based abilities.

Fully separating from a host is an hour-long process, at the conclusion of which the symbiote must succeed on a DC 10 Constitution save.

While it is tightly bound to its host, the symbiote may uncover small parts of the body it is controlling, most notably the head for the sake of interacting with humanoid society without being noticed. If it leaves the head uncovered for more than an hour at a time, or suffers any fire damage at all, the host stirs in its sleep and gets another Wisdom saving throw to repel the symbiote. If the host succeeds the symbiote is forced from its body in a highly rushed fashion, totalling one minute and leaving the symbiote with one level of fatigue. It may not attempt another bonding within 24 hours.

This is all pretty rushed. But what do you think of the basic elements?

[Garfunion]

So are you trying to make a race?

Might I suggest you take a look at the Spore Druid. It could easily be re-skinned/tweaked to fit a “Venom” theme.