Unbeknownst to Sun Wukong, he was using his Divine Skills, seeing through Hu Ji's true form.
Under his fiery, golden gaze, Hu Ji was cloaked in white bones, existing between a demon and a ghost, clearly under someone's control.
To control a late-stage Heavenly Immortal of such caliber without the Great Sage Buddha Stupa noticing, the person must be incredibly powerful.
Upon reflection, Sun Wukong surmised that perhaps only the Black Bone Lady possessed such Divine Skills and Spells to control Hu Ji.
Or maybe Hu Ji was simply an avatar of hers, deliberately arranged to take the life of the Great Sage Buddha Stupa.
Such stratagem was truly terrifying, considering how the Great Sage Buddha Stupa and Hu Ji had met and married, surely laid out before the new Buddha convention; such cunning and methods were indeed frightening.
As he pondered this, Sun Wukong suddenly felt a gaze upon him and looked up, meeting Hu Ji's enchanting and bewitching eyes.