A short walk downstream from the main staircase. The church takes its name from a fresco of damned souls being tormented by serpents — graphic enough to make it one of the most photographed paintings in the valley.
The rest of the interior shows the Last Judgement on one wall and a series of saints on another. The paintings date from the late 11th century, when the valley was still part of the Byzantine Empire and the local Greek-speaking monastic community was at its peak.