Invisibility
An invisible creature is impossible to see, allowing them to go unnoticed even in close settings. But they are still physically present and still make noise. An invisible creature will always make DEXTERITY (Stealth) checks at advantage. Advantage means roll a d20 twice and choose the higher roll for your check.
Anyone attempting to find an invisible creature makes WISDOM (Perception) check at disadvantage. Disadvantage means to roll a d20 twice and choose the lower roll for your check.