The Invisible Enemy (VHS) The Invisible Enemy (VHS) Login to add to your collection or wishlist! Where to buy This site contains affiliate links for which I may be compensated. Search to buy on Amazon UK Search to buy on eBay UK Stories in this collectable: Classic Who S15 • Serial 2 · (4 episodes) The Invisible Enemy Average. Rating: 52% Average rating: ★ 2.93 Watch Watched? 0.016304969787598