killer bringing home cats and nightmare naming them after prescription pills. there's also just one called fentanyl

nightmare being very antsy about his birthday. killer presenting him with a wet sopping trout as a "gift" in a crude attempt to cheer him up

nightmare assigning killer perfectly safe yet physically exhausting tasks for the fun of it

killer harassing nightmare in every video game they play. nightmare obstructing his progress however possible so they're both equally annoyed

sadomasochist duo who use each other to vent out their anger

killer making up random slang words and nightmare spending half the day trying to figure out what he's saying

nightmare having delusional episodes and killer going along with whatever he believes for the hell of it

nightmare calling killer a rabid dog and waking up the next day to him chewing on his arm

killer bringing nightmare a bouquet of dead floweys for valentines day

killer jokingly starting a church in order to pray to nightmare. nightmare almost killing him before realising that killer somehow managed to get people to start attending

giving each other the silent treatment after every argument. nightmare is always the first to cave in and start a conversation

killer having a dream cosplay and popping out in front of nightmare at the most random of times

killer filling nightmares office with thousands of balls meant for ballpits

killer conspiring with dust to make a chemical capable of melting nightmare's goop. he succeeds and nightmare loses his mind over how the first person to successfully melt it is killer .. because his reasoning was 'it would be funny'

they'd have a political podcast consisting of nightmare being serious and killer responding with arguments specifically designed to annoy him

nightmare being woken up at 2am because killer wants to go to a random au and look at paint splotches

nightmare going on vacation. error launching killer at him and screaming about how he refuses to listen to anyone else. nightmare being stuck with killer on vacation

nightmare showing killer a show he likes. nightmare occasionally sparing glances to see if he's watching or not — killer being disinterested in it and side eyeing him the entire time watching his reactions instead

the pair having equally as much information on bugs and freaking people out with it

nightmare ballroom dancing with killer during one of their many, many massacres

killer throwing paint over nightmare and learning that he can indeed dye his sludge to be any colour

killer learning that nightmare has vocal stims and repeating nonsensical things to try to get him to repeat involuntarily or vice versa it could go both ways

both of them having vocal stims and the moment one of them stims the other starts too

nightmare stepping away from his paperwork just to supervise killer cooking

nightmare inherently despising furries because they're having fun expressing themselves freely. killer buying a fursuit that looks suspiciously similar to nightmare and wearing it

killer putting said fursuit into nightmares closet and proceeding to show it to the other bad sanses. nightmare finds out what happens later and almost kills every member of his gang

nightmare being lighter than usual thanks to his lack of physical form, killer waiting until he's asleep and proceeding to figure out how many balloons he has to tie to him until he starts floating

nightmare standing in the corner of killer's eye and teleporting away if he looks at him. this repeats for hours

nightmare insultingly saying that a roomba could do a better job than killer, so killer buys one. the roomba, in all its glory, does indeed somehow do a better job than killer

nightmare getting used to being called a squid/octopus. nightmare almost exploding when killer calls him a centipede

horror getting captured by the enemy and nightmare leaving him there for a week before getting him out. killer getting captured and he's out within 2 hours

nightmare being the type to never swear. killer amping up his chaos and managing to get him to swear five times in a day

killer stealing aphrodisiacs from dust, slipping them into nightmare's tea and proceeding to draw all over him. bonus the drawings melt into the goop and nightmare has cool looking drippy symbols on him for the next few days

killer putting nightmare on antidepressants end sentence there's too many outcomes to list

killer hiding nightmare's clothes in an attempt to get him to walk around naked. nightmare somehow having an infinite amount of the same outfit (it's just his sludge—the others were there for show)

nightmare bandaging killer up badly on purpose in hopes his wounds reopen and he starts bleeding

killer having an organ he teleports with him essentially everywhere just to play boss music for nightmare. nightmare being forced to deal with it because the one time he didn't bring it along killer refused to fight alongside him

killer and nightmare being the greatest poker duo of all time. they set up a gambling ring where people can just watch them play against each other

killer making a vocaloid out of nightmare's voice and releasing it to the public, which obviously gets a bunch of attention since it's, well, nightmare. killer starts making songs with it and gaining recognition except it's literally just nightmare himself singing them

killer holding a funeral for nightmare whenever he gets mildly injured

both of them making up the craziest lies about themselves and seeing how long it takes for the other to figure it out

nightmare going by they/them and killer, having special permission to call him by he/him, going around correcting people on 'his' pronouns

killer with a gun. nightmare having to get it away from him before he kills his teammates

"what if we get a new teammate" "no"

killer being a really horrific chef yet somehow when it comes to preparing food for his and nightmares monthly picnic it's all perfect