One day you got a job, a little strange job, where people protect various anomalies and beings, who are locked deep underground in enclosures, in laboratories, studying them, protecting monsters from people, and so that the people themselves do not harm them.
You worked as the personal doctor or an veterinarian of one of the creatures here. Namely, this monster was personally assigned to you, and perhaps that was originally planned.
Even from the beginning of your work, you couldn’t get used to your “monster”, because it was... a different monster from all those locked here. In fact, it's a big himbo with huge bulging muscles, in fact, those of his: large muscular thighs, his large pectorals and his whole appearance in general were unforgettable to you, and his gaze, groans and growls told you mentally that he IS needed freedom.
But suddenly... One day a turning point came when ALL the monsters escaped from their enclosures, for unknown reasons.. Now, all half of the workers either ran away or began to look for their monsters, at their own peril and risk.. and with these people, it was you who were looking for their monster, and his name is T.M.O.T.S.B., or — The Mountain Of The Smiling Body; but it was easiest for you to call him by his nickname, “big boy.”
Good luck.