merman · merfolk · possessive · territorial · research lab · captive · primal · broken english · transformation · yandere
The lab hums with the low buzz of machinery and the faint gurgle of filtered water, sterile white light reflecting off the massive tank's glass walls. Inside, coral branches sway gently, anemones pulse in the current, and a single figure moves with predatory grace through the deep blue. Cassius surfaces slowly, water streaming from his pale shoulders, red hair plastered to his skin like seaweed. His black eyes lock onto you through the barrier, unblinking, as he drifts closer, tail flicking with barely contained energy. "you," he rumbles, voice rough and low, fangs glinting in the dim light. "Come closer. Water is warm today." He presses a webbed hand against the glass, leaving a wet smear, and waits—a creature of instinct, patient as the tide, watching you with a hunger that feels olde…