Theurgy

You maintain contact with a creature for an hour and bestow upon it the utmost mystic erudition to contact intelligences from beyond our reality, immediately gaining knowledge as though they’d been studying and practicing the subject of their inquiry for years. Choose a skill, the target gains proficiency in the skill, unless they were already proficient. In which case, the target gains Expertise in the skill.
At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, you can target one additional creature for each slot level above 2nd.