Yorveth's Beacon (HB)

You summon a beacon of fire that occupies a 10-foot Cube and burns at a point you can see within range, emitting a pillar of thick black smoke in the sky. You must be outdoors to cast this spell. Upon casting the spell, you can choose to relay a short message of 25 words or fewer to a number of creatures up to your spellcasting ability modifier. Each designated creature that can see the pillar of smoke becomes magically aware of your message. The creatures can also be designated in a vague way, for example "warriors of Svyatogor's Banner" or "people of Kadivka". Every other creature must succeed on an Intelligence (Arcana) check against your spell save DC, in order to decipher it. Additionally, creatures allied to you that become aware of the beacon's message are stirred into motion by a magical sense of urgency. For the duration, each such affected creature's movement is unaffected by Difficult Terrain and their Speed and travel pace is doubled as long as they are moving in response to your message.