Awaken Monstrosity

After spending the casting time tracing magical pathways within a precious gemstone, you touch a Huge or smaller Monstrosity that lacks Legendary Resistances and Legendary/Mythic Actions. The target must have an Intelligence of 3 or less. The target gains an Intelligence of 10. The target also gains the ability to speak one language you know.
The awakened Monstrosity is charmed by you for 30 days or until you or your companions do anything harmful to it. When the charmed condition ends, the awakened creature chooses whether to remain friendly to you, based on how you treated it while it was charmed.