Night Roof

The night roof only has one level, which is when you're playing Dr. Zomboss. There is a Survival mode on it, but that is a secret level. In the level, you will only get one mushroom: the Ice Shroom. When Popcap was making the game though, they chose for it to be night because of the time when Dr. Zomboss breathes fire and ice balls at you, you need the Ice Shroom to melt the fire balls but they could've just used the Coffee Bean instead and made the level daytime, but then it would be harder.