Bob faces a Mythos entity and has to make a Stability test or lose 7 Stability. It’s been a long day and Bob is already at -2 Stability. Bob’s player chooses to spend 4 Stability points in order to (probably) automatically succeed on the test, bringing him to -6. This means that despite the success, Bob’s mind is blasted.
But was this a mythos shock?
Here’s basically all the rules say on mythos shocks, and why it matters:
Each time you are blasted by a Mythos encounter or attack (when your Stability drops to between -6 and -11), your Sanity rating drops by 2 points.
If you lose a Logos card, does that card always become a Mythos, or can you trade a Logos for a Logos? For example, if I lose my Routine: Dead End Job, can I replace it with Routine: Homeless?
If a character has a superpower of mental swiftness, does this fall under the Mobility Mythos?
7th edition Call of Cthulhu rules give two mythos skill increase values for each mythos tome: CMI (initial reading) and CMF (full study). The general principle is clear: you gain a bit of knowledge from a basic skim of the book, and significantly more from a deep dive into the horrible content therein. What is not entirely clear from reading the rules is whether the CMI value is contained within (ie. is a subset of) the CMF value.
For example, suppose a tome has CMI +5 and CMF +12. Jim skims through the book and gets +5 to his Mythos skill. When he completes a full study, does he then gain another full 12 points of mythos skill (for a total gain of +17)? Or does he gain an additional 7 points (bringing his total points gained from that book to +12)?