Page 128 - Solar Vendetta

Nightmare Moon: Remove the sun, enforce night eternal.
Dragon: Cover up the sun with smoke.
Discord: Switch the sun and moon really quickly.
Chrysalis: KO the sun pony.

The sun seems to be the yardstick for trouble in Equestria.

Applejack: Let me get this straight – a dragon set up shop between last night and this mornin’?
Rarity: Has this dragon been around here long, or did it just… move in?
DM: …You’re on the right track, at least. A dragon recently built a new nest in this mountain, but that’s not why there’s smoke in the sky today. Sometime between last night and this morning, the dragon settled down for its NAP.
Twilight Sparkle: The dragon is sleeping, and it’s snoring out smoke.
Pinkie Pie: Huh. Talk about getting your beauty sleep.
Rarity: Ugh, that joke was simply painful…
Rainbow Dash: So what? How can a non-rampaging dragon be a problem?
DM: Dragons can sleep for up to 100 years at a time. By the end of the next day, all of Equestria could be covered in a dark haze.
Applejack: So, 100 years of dark instead of “eternal” dark, huh?
Pinkie Pie: Is anyone else getting that “bells ringing” feeling?
DM: Hahaha Ihavenoideawhatyou’retalkingabout.