Druidic is a Druid feature gained at level 1 in D&D 5e. You know Druidic, the secret language of druids.
You know Druidic, the secret language of druids. You can speak the language and use it to leave hidden messages. You and others who know this language automatically spot such a message. Others spot the message's presence with a successful DC 15 Wisdom (Perception) check but can't decipher it without magic.