automatically find n link posts mentioning other ppl and quietly insert those posts into the target's so any talking behind someone's back gets back to them, but do it at some delay and with deniability- it was just bad luck that they came across the thread abt how they suck
or do the Local news thing of foreboding headlines but making it difficult / delayed to obtain the relevant details abt some novel threat, maybe like "3 ppl are talking shit abt you, earn or buy 5 tokens to see what they're saying"
train a model to predict when ppl are abt to log out in frustration and intercept them just beforehand w a burst of support from new (secretly bots if necessary) allies or an unexpected win
come up w pernicious UX details so that it is easy to do annoying things that affect others in the group, keep changing them up so there's always some new rule and someone blundering and someone intentionally pushing the annoy-a-tron button- think like hellthreads before thread mute
once all the pvp drama is going well, play innocent and insert an insipid "moment of zen" interstitial right when ppl are riled up... done correctly this speedbump will be triggering rather than relaxing
play ultrasounds (just above hearing range) unpredictably and in a discordant manner for subconscious annoyance; also use slightly mismatching colors to create jagged unbalanced patterns at the edge of perception