This is part 2 of the 'Venom' doodles I did a little while ago. (If you can't see part 1, it's bc I put it under a mature rating due to gore)

Plague is an OC, they have the ability to absorb bacteria and viruses, quarantining them inside their goo/pores, of which they can disperse back into the air, or inject into liquid.
One day they meet their host, Mars, who is an assistant cook with germaphobia - this lead to a few freakout sessions and boundary-pushings when they first bonded, including one instance where Plague decided to pull Mars into a puddle of mud, but after a while he discovers that it's not so bad since Plague is able to essentially sterilise objects and surfaces, which has really helped with his anxiety due to said condition.
In addition, knives are their go-to weapon, since Mars owns a bunch of them (since, you know, cooking) and they're pretty fun to use.