The Cos: Consent, Conflict, Combat, Cooperation, Communication
At its heart, Heroes MUSH is all about cooperative storytelling. When in-character conflict arises, it's important to remember, OOCly, what we're here for: that same cooperative storytelling!
As we know, combat happens. Conflict makes for run RP! With a multitude of crazy powers in the mix, it becomes even more important for players to be on the same page. The same applies to battles of a less obvious nature: willpower, influence, athletics. In lieu of stats to make official decisions for us, it comes down to realism and communication. You should know if your character is strong or weak-willed, if they're no good at first aid, or if they're suckage at bluffing. If they're a bad liar, don't have them skilfully tricking another character with lies; it's unrealistic and not fair.
There are easy ways to keep things flowing smoothly while still being fair, of course!
It's good etiquette (and typically required) to pose trying to affect another character rather than writing it as if it definitely happened, unless it's pre-planned and agreed on between all parties. The key is not to assume. Example: Jane picks up the chair and swings it with all her might, spinning toward Joe's face.
It's ultimately up to Joe's player whether or not the chair hits him or not. However, the factors of reality are to be considered. Is he slow because he's injured? Is he cornered where it would be hard to dodge? Is Jane strong and fast, or is she clumsy? If Jane missing Joe would be unrealistic, it would be sensible of Joe's player to pose him getting hit. In another scenario, if Joe took great lengths to hide, Jane shouldn't walk in and automatically see him.
In-Character Actions do equal In-Character Consequences, so use common sense! There's usually an alternative that works, story-wise. Talk it out! Hurting, killing or otherwise putting someone in a position they adamantly don't want their character to be in OOCly won't be tolerated. If, however, you feel a player is being unfair (forcing a character into a position OR unwilling to accept realistic consequences), contact staff. We'll help you work it out.
Special abilities are no different, except that you can optionally +roll your stunts. If you don't know who "should" win out or fail, or simply want a wildcard to help you decide how your power works in a particular scene, +roll if you like! It's unofficial, simplified and fun; see news stunts for more.