You strike up a conversation with a creature of your choice. This chosen creature must have an Intelligence of 5 or higher and be able to understand your speech. If the creature's intelligence is lower than 5, it will hear the normal words you speak, sans enchantment (we'll get there).
As you speak, you weave threads of enchantment through your words. Choose a power word that will end the spell, and weave that in, too. Your conversation will sound normal to passersby who do not prevail over the dice on a successful DC 15 Arcana (Wisdom) or Investigation (Intelligence) check. As you talk about the weather, armor, or the exceptional service at the tavern down the way (just some examples), secretly command the creature to do a simple task, such as "attack the tiefling in the white cloak" or "pass this paper to the half-orc in the back."
After the command, the creature in question must make a Charisma saving throw every time it has a turn (this spell is only effective on creatures with a Charisma of 16 or below). If it succeeds, the spell ends and it forgets everything that has happened. If it is killed, wounded, or magically forced to hurt itself as a result of a command, the spell ends with the same effects as previously stated.
When you are finished with your proxy, end the spell with the power word. The creature will not remember what has happened.
AT HIGHER LEVELS: When using this as a 6th level spell or higher, wounding the proxy (not as a result of the spell) does not affect the spell, unless the creature dies or is unable to perform the task as a result of the injury.