The Jet-Black Shadow Invades Tokyo

The Jet-Black Shadow Invades Tokyo (東京侵食 漆黒の影, Tōkyō Shinshoku Shikkoku no Kage) is the sixteenth episode of Digimon Adventure:

Summary
Taichi’s team finds a strange cave that leads to Tokyo. Excited to be back, the children attempt to get home through the subway. However, a creepy Digimon prowls the city, and there, the children learn a shocking truth.