Bowser has bad memories of when he was possessed after watching "The Exorcist".
Is there even a shroobified Bowser?
After Elder Princess Shroob is beaten, she turns into a mushroom, which Bowser eats, not knowing it's her. She then possesses his body, and Mario and Luigi must defeat the possessed Bowser (Shrowser) and her ghost.
it can and it did, more than once
Lol, this just made my day XD
Bowser Cry Poor