This is a short fanfic I wrote back in April of 2014.
Mario was walking along a huge stretch of World 2 desert, Luigi trudging along at his side. "Hey, bro, don't you just hate having to save Peach so much?" Luigi asked. "Every year, it's the same thing..."
"Don't be like that, Luigi," Mario responded. "If it weren't for this job, we'd still be plumbers back in Brooklyn!"
Luigi shuddered. "Ugh, Brooklyn. If we never went back there, it'd be too soon."
"... Hey, Luigi," said Mario a few moments later. "Is it just me, or is the sun getting... brighter?"
Luigi looked up at the hot, blistering sun. The giant ball of fire seemed to move closer and closer before it suddenly grew an angry face and lunged at the two brothers.
"Mario, LOOK OUT!"
Luigi quickly pushed Mario out of the way. The Angry Sun passed through Luigi, burning him almost to death before hovering away.
"Crap!" Mario ran over to Luigi. He quickly got on his knees and held his little brother's head in his lap. "Luigi, don't die on me!" he cries. "You're gonna be okay, I promise!"
"It… doesn't matter… "
"Don't talk like that, you're scaring me!"
"No, I mean it really doesn't matter… I have a ton of extra lives…"
"Oh."
"I just need to say one thing… Before I respawn…"
"What is it, bro?"
"... It's back."
Luigi's body went limp. Mario began to cry before he realized the meaning of his brother's last words.
"Oh, shi-"
The Angry Sun suddenly swung back into Mario, burning him to a crisp.