Degenerative disc disease (DDD) is highly prevalent. If conservative treatment fails, spinal fusion procedures are commonly performed. Total disc replacement (TDR) might be a surgical option for a distinct subset of patients with DDD. Several prostheses have been or are still available. Despite some promising initial clinical results, there is still limited experience with hardware-related adverse events. This report highlights an unreported complication after TDR with a viscoelastic device. Literature about long-term outcome and safety of this particular TDR is scarce. Hence, there exists limited experience with TDR-related complications with such a failure mode. We report a 34-year-old male presented to us with an acute S1 radiculopathy on the right. His past medical history was significant for prior TDR at the level L5/S1 at another hospital 2 years prior to this acute episode. Imaging studies revealed an intraspinal mass compromising the right S1 nerve root. This mass mimicked a disc herniation and sequestrectomy was performed. Intraoperatively, the prolapsed sequester turned out to be part of the viscoelastic nucleus of the disc prosthesis. Interbody fusion combined with posterior instrumentation was ultimately performed. The patient did well afterwards, but is currently (2 years later) developing adjacent segment disease with facet syndromes. Since TDR might be beneficial for certain patients, spine surgeons should be aware of potential device-related complications.