10 Times Marvel And DC Secretly Crossed Over
1. The Flash Travelled To The Marvel Universe
At the end of Crisis on Infinite Earths, the Flash got one of the greatest deaths in comics. He created a speed vortex to destroy the Anti-Monitor's cannon and save multiple universes, but in the process dissolved into pure energy.
Like a lot of characters, he came back to life a few years later. Unlike a lot of characters, it was in a different company's book.
In Quasar #17, the intergalactic hero found himself watching over a race to find the fastest being in the universe. The race was stopped though when a man appeared in a flash of lightning in the middle of the track.
The man was clad in the tattered remains of a red and yellow costume and when Quasar asked who he is, he said that all he could remember was that his name sounded something like "buried alien".
Yeah, they weren't even trying to be subtle with this one. The issue is based on the idea that, instead of dying, Barry Allen ran so fast he crossed over into the Marvel Universe. The entire comic acts as a tribute to the character, The Fastest Man Alive even wins the race against all the other speedsters.
He then took up the name Fastforward and was never used again because other writers were way more afraid of copyright lawyers than Mark Gruenwald was.