I wanna try it out but I'm not brave enough to do it directly in my OS. WHat would happen if I did it in Ubuntu inside a VM? What if VirtualBox has mounted some

I wanna try it out but I'm not brave enough to do it directly in my OS. WHat would happen if I did it in Ubuntu inside a VM? What if VirtualBox has mounted some directory on my system to the guest? I'm afraid to try this too :/ I once tried 'format C:' on a Windows 10 laptop I didn't care about and I just got a boring error message.