Oh, a pet mimic would be amazing - [forgetting for a moment that such a creature is not a thing here] - it'd be excellent for guarding your things while you are away or if you were in a sticky situation and needed to fool someone.

[in a silly bad guy voice:] "Hand over the such-and-such!" So you turn and give your mimic a wink and a nod and it turns into a perfect copy of whatever it is and you had it over, and as whoever it is inspects the "item" - [he does little air quotes with his fingers] then the mimic reveals itself and attacks! And then you have the advantage to attack or make an escape, whatever you choose!

[He's very animated as he recounts the hypothetical, like he's definitely considered this before.]