Day 1: 'Gamer'
The shrunken Button Mash grumbled as he sat on Sweetie Bell's shoulder, plotting with his new 'game controller'. Sweetie Bell is too busy herself to notice, playing some SMASH BRONIES on the couch. Button whispers the command, and the plug end of the control snakes up Sweetie's neck and settling right next to her ear before the mare notices.
"Hmm?" Sweetie says, glancing at the plug...far too late. "GAHHH!"
That is all she can say as the plug strikes like a snake, plunging into Sweetie's ear and wiggling right through and deep into her brain. With a wet 'PLUNK', the controller connects to the brain, hacking the mare's mind and enslaving her to the evilly laughing Button Mash. Sweetie Bell stands to attention and starts to march outside, controlled by the tiny pony gamer with the controller on her shoulder...
Eris: "Brainwashing gamer controller. Not bad."
Discord: "Thank you. In that universe, Button Mash had been shrunken by Sweetie Bell experimenting with one of Twilight's potions. She kept him as a pet all through their childhood and into adulthood. I figured Button deserved some 'payback'.~"
E: "Hehe. Well done. Ok, on to the next one. Your word is, 'Instrument'..."