NASA’s Chandra observes a ribbon of X-ray emission behind a galaxy in the galaxy cluster Zwicky 8338*. This X-ray tail is thought to be caused by gas stripped from the galaxy moving through hot intergalactic gas. The ribbon of X-ray emission is 250,000 light years long.
*Fun fact: Fritz Zwicky was the first person to infer the existence of dark matter, using the virial theorem! (a theorem which I can’t bring myself to liking because the name reminds me of viruses, so I feel like it might give me the flu or something)