Fighting critters can cause your stats to change when you get infected.
Stats prefer to go up rather than down, if you have more, say, strength than something and you lose to it and strength is rolled, there's a 90% chance your strength will NOT change, and a 10% chance the strength drops a point.
Going the other way, your strength would always raise if rolled. Be as strong as a snake man!
PS: Someone hurled 10$ at me, thanks man, big thanks, you totally made my day!