Part 2 of 2. The two-part episode The Zygon Invasion concludes tonight (if you missed Part 1, it’s repeated at 8 p.m. ET, before the start of tonight’s wrap-up). The Zygons are shape-shifters, which, considering their original shape (pictured), is understandable. But my question is, is the Clara we’re watching our familiar and beloved companion to the Doctor – or a shape-shifted alien?