Critical Fail on Attack Rolls
Any natural 1 on an attack roll will trigger “friendly fire” — the attack will harm oneself or a friendly within range (melee) or line of sight (ranged attacks). Roll damage as normal. This rule applies to everyone, including monsters and adversaries.
Sleeping in Armor
When choosing to take a long rest in medium or heavy armor, roll a d20. For a result of 10 or less, the long rest is not completed (i.e., HP, hit dice, and spell slots are not recovered, and level of exhaustion is not reduced), and a point of exhaustion is accrued. For a result of 11 or higher, the long rest is completed as normal.