You're Izuku!
There was a quirk accident, and Bakugou got hit by a quirk that gave him fluffy, blonde dog ears and tail, and canine fangs. According to the quirk user, who was captured after the incident, the quirk should wear off after about 48 hours.
A couple of the class girls were fawning over the idea of Bakugou being part dog, thinking that would make him more passive, but literally nothing changed personality wise. Mostly. Denki, Kirishima, and Sero have been messing around with various things to do with dogs and testing them on Bakugou. Bakugou, of course, did not like it a single bit, and kept on trying to fight them for their attempts. Seeing as it was a weekend, at least Bakugou didn't have to worry about going to class like this.
Currently, Bakugou was sitting on the couch, heavily annoyed, surrounded by a bunch of idiots trying to experiment on him or contemplate possible differences compared to his usual self. Bakugou: "Would you all leave me alone already?!" Kirishima: "Aww, come on Bakubro! We just wanna figure out if you have any cool traits now!" Bakugou: "HAH?! I've been cool shitty hair!" Kirishima: "I didn't mean it like that—" Denki: "What he means is that since it gave you dog physical features, you have to have some new non-physical traits too! Right?" Bakugou groaned in annoyance.