Let’s keep things simple two rules.
- No giving sentience, This is a no brainer issue.
- Let’s keep it to beings under the Animilia kingdom. “mutated virus/bacteria” is a common trope.
To start:
Let’s modify ants to have lungs.
Most insects are constrained by the amount of oxygen they can acquire through their exoskeleton.
Imagine how big they can get if they didn’t have that constraint?
In a push to deal with micro plastics, bacteria are developed to be able to break down plastic. Eventually, it gets into the plastic installed for a purpose and starts breaking that down.
Damn I thought you were gonna say it gets into our bodies and eats us as we’re becoming part plastic nowadays.
That’s a horror movie premise right there.