Hex Effects: Or, Side Effects of the Amateur Alchemists. Officially. Or, unofficially, When Family Rivalries Can Only Be Settled By Giving Your Relative an Evil Alter Ego! Amongst other miserable maladies.
Hex Effects is a game which you start afflicted, and spend trying to treat your own Hexes. As you do, though, each Remedy will leave you susceptible to other Hexes, which the other players will so ungraciously give you, while also triggering your untreated Hexes with Disasters to garner an effect. There really is no winning, is there? Only there is, because it’s a card game! The first person to treat all their Hexes wins. Take that, meddling relatives!

This one is relatively simple for something that goes back and forth so much. There are a few other ways to mess with other players and/or benefit yourself – usually ‘and,’ they’re very much joint concepts – and precious few things to keep track of that aren’t directly in front of you, rendering it rather easy to pick up! While also being a “plan six steps ahead, if you wish” (“…and if the deck favors you”) kind of options-transparent. The design is similarly details-rich combined with easy-to-parse!
(My favorite such detail at the moment is the tagline on the Remedy for Sinister Spores, Eau d’Acide No 7, which merely reads: “Sacré burn!”)