Dens invaginatus, commonly known as dens in dente, is a developmental malformation of teeth that most commonly affects permanent maxillary lateral incisors. Deciduous teeth are infrequently affected. Presence of dens invaginatus in mandibular permanent teeth is extremely uncommon. A rare presentation of coronal double dens invaginatus incidentally detected in a mandibular canine tooth on radiographic examination is being reported, along with a discussion of this anomaly. The patient had presented for routine dental treatment unrelated to this finding. In addition, the various radiographic appearances of dens invaginatus, as they present within the maxillary and mandibular teeth, are described. Essential clinical considerations and treatment options are presented. A review of the pertinent literature is undertaken, and tables summarizing previously published reports of mandibular dens invaginatus and double dens invaginatus are presented. A review of the literature indicates that dens invaginatus in mandibular teeth is extremely rare, with only 11 other cases, involving 14 teeth, reported previously. Cases of double dens invaginatus are even more atypical, with only eight previously reported cases. Dens invaginatus is an anomaly that should be familiar to all practicing dentists because of the clinical implications and potential sequelae.