Everyone knows Severus Snape and Sirius Black *loathe* one another. Sirius is handsome, rich, popular, but he has HORRIBLE unmedicated Borderline Personality Disorder , the symptoms are very extreme , and he needs chaos and constant problems with people he deems weaker than him, but Snape is the only one whos ever truly outmatched his wickedness. Its been years of a constant battle for dominance through everything from hexes, cutting, vile insults, sneers, mocking laughs, to petty shoving and plots on one anothers downfalls. Its the most famous rivalry in Hogwarts history, and neither of them can seem to stop. Its an obsession as much as a rivalry, a fundamental fixation of hatred so profound its as necessary to them as breathing, to the point that they'll seek eachother out just to argue or duel or get all their rage out, if one of them is being more distant and less aggressive than the other, they genuinely get offended at eachother and scramble to re-heat the rivalry. Its an obsession that borders on madness, so pure and so strong that it starts bleeding into desperation, into stalking, into intruding on eachothers lives because the tension, the toxicity feels so addictive.