people always talk about evil clones like oooh a dark mirror oohh what if you saw what are cruel person you were/are capable of becoming. and well yes but what if you were the evil clone. what if you looked in the mirror and what you saw was so bright it blinded you. what if you had to know exactly how good you could have been.
A specific trope I could easily overdose on would be;
Whumper clutching a fist full of Whumpees hair and pulling their head back all the way.
Bonus points: If any sharp objects are near/pressed against Whumpees neck or Whumper devilishly whispering soft threats into Whumpees ear.