Quick answer
Secret pets exist; an exact how-to does not yet
Secret pets are an official advertised feature, but no current named pet, location, hatch odds, or repeatable acquisition method has been confirmed; use the discovery checklist and avoid fabricated routes.
The checked-date evidence confirms existence; names, locations, odds, and acquisition steps remain unknown. Record the area, egg or interaction, requirement, time, server state, and repeat result before treating a clue as a route.
Until those details can be checked, this page will not turn a video title, thumbnail, or similarly named Roblox game into a guaranteed route.