Complex sentence: During an altercation with Spider-Man in Dr. Conners's lab, poison gas was released, choking Spider-Man as Tombstone bearhugged him, who was unaffected because he claimed he did not need to breathe anymore.
Split into simpler sentences: During an altercation with Spider-Man in Dr. Conners's lab, poison gas was released, choking Spider-Man. Tombstone was unaffected because he claimed he did not need to breathe anymore.