A plunging ranula is a soft-tissue mass stemming from a mucous extravasation cyst of the sublingual gland which can herniate through the mylohyoid muscle. We describe a case in which a 14-year-old girl presented with a rapidly expanding mass on the floor of her mouth affecting her ability to swallow and speak and causing tracheal compression. The patient was initially managed conservatively with antibiotics and steroids; however, the mass continued to expand necessitating emergent bedside incision and drainage and subsequent surgical intervention. The pathophysiology and management options for ranulas are also discussed herein.