I have this small green "patch" growing next to my strawberry (the "small fruit" type). It looks like it has tiny leaves and small fluff, and is still embedded into the soil, but it's slowly growing and another one popped up a bit away.
There's no other plant in the same pot, so I was wondering if it's the result of an underground runner, but everywhere I looked I never found anyone talking about underground runners.
Note
The original strawberry plant is slightly elevated (an inch or two) above "ground level", and this patch is on ground level.