Complex sentence: Right after the Extreme Rules match against Styles, Reigns was attacked by the returning Seth Rollins, whom he dropped the WWE World Heavyweight Championship at Money in the Bank, ending his reign at 77 days.
Split into simpler sentences: Right after the Extreme Rules match against Styles, Reigns was attacked by the returning Seth Rollins. At Money in the Bank, Reigns was defeated by Rollins, ending his title reign at 77 days.