A sort-of prompt from tumblr user guardiankarenterrier. Thanks for the idea!
"Ugh. Yet another day of disgusting cafeteria food," Sam muttered as a questionably vegetarian slop was plopped onto her plate. "The monotony wears on."
"Wow, you're particularly Goth today," Tucker said, sliding his tray along beside her. "Bad weekend? I didn't see you a lot."
"Yeah, well, family time and all that. When my mom heard Danny was off on a family road trip she jumped at the opportunity. We painted nails."
"But your nails aren't painted."
"Not anymore," Sam said darkly. Then she spotted a mess of jet black hair sitting at their usual table. "Hey, Danny!" she set her tray down next to his, with Tucker across from her. "I thought you wouldn't be back until tonight. Not that I mind."
"Yeah, well, I started getting this really weird rash so we cut the vacation short. But I still have to go to school." he itched absentmindedly at his chest.
"Are you sure you should be here? You look kinda pale." Sam said worriedly.
"Eh, I'll be fine." he brightened a little. "My dad actually packed my lunch today. Can you believe that?"
"Uh, no," Tucker said, eyeing the brown sack warily. "Are you sure you should eat that? There might be ectoplasm in there or something."
"My mom said she supervised," Danny said, shrugging. "Besides, a little ectoplasm never hurt anyone, right?" he winked at Sam and nudged her a little.
"I have no idea what that was supposed to mean."
The three of them continued to chatter on as Danny pulled out perfectly normal lunch items: a sandwich, a container of applesauce, and a capri sun.
"See, Tucker?" Danny said, pulling out the sandwich, "perfectly normal."
"Wait, Danny aren't those-"
Danny looked up at his friend, already chewing a large bite of sandwich. His eyes widened, and he looked down at one of the red flowers hanging out of the bread.
"AAAGH!" he screamed as red smoke billowed out of his mouth. The cafeteria chatter died down as he stumbled over to the nearest trash can and spat out his sandwich. But he must have accidentally ingested some. Sam and Tucker could hear retching.
"Billions of people in the world," Sam said wearily, "and Danny gets the set of parents who unwittingly put blood blossoms in his food."