One leaf plant.

That looks like its reveging do to light leaking somewhere boss

Not very well is she, it take major shock from major stress overload to cause this could be many things what springs to mind for you?

yeah, re-vege or something terribly stressfull to cause a 1-finger leaf and smooth with no serated tips. if it's an autoflower, it may have some fucked up traits, lol... if it's a photoperiod, you probably have some light pollution during dark cycle -- flood light in backyard turning on with motion sensor?

Ist eine Mutation ,aber sie wird wachsen und wird soweit ich weiß keine Beeinträchtigung haben

I heard it can happen when you do reveg , did you change the light time in some unnatural way ?