What happens if multiple concentration checks are required from different sources while a caster is trying to cast a spell? For example, if we have a (very unfortunate) wizard who is trying to cast Freedom of Movement while concurrently:
- On fire, taking 1d6 every round (on average a DC 16 concentration check)
- Grappled by a Giant Squid (CMD of +22, so a DC 36 concentration check)
- Entangled ( a DC 19 concentration check)
- Casting Defensively ( a DC 23 concentration check)
...What rolls does the hapless wizard have to attempt?
I've seen various posts on the paizo forums and reddit stating all manner of conflicting answers, ranging from stacking DCs together, only caring about the highest, and (what seems closest to RAW) rolling against each effect. What is the correct number and DC of concentration rolls in this scenario? And, failing official rules, I'm sure that the PFS has a mandate on how to handle such a situation, though I cannot find one.