(1995-1996)

Throughout most of 1995, the Undertaker was feuding with members of Ted DiBiase's Million Dollar Corporation, including IRS and King Kong Bundy. At WrestleMania XI, while Undertaker was facing Bundy, Kama Mustafa stole the Undertaker's source of power, the urn, and disrespected Taker by converting it into a large gold necklace. The two faced each other in a casket match at SummerSlam. After putting on a great match, the Undertaker finally came out on top, closing the lid on Kama. Several weeks later, the Undertaker was assaulted by Yokozuna and King Mabel, which led to an injury of the eye orbital bone, forcing Undertaker into a period of absence for surgery. The Undertaker returned a while later wearing a Phantom-like ghostly grey upper facemask and defeated all of his competition. In 2002-2003, Kane wore a similar mask that was colored red and black.

The 1996 Royal Rumble saw the unmasking of the Undertaker in a WWF Championship match against Bret Hart. Diesel interfered in the match, costing the Undertaker the championship. One month later, while Diesel was facing Hart in a steel cage match, Undertaker came up from under the ring to drag Diesel underneath, allowing Hart the victory. This led to a match between the two giants at WrestleMania XII, in which the Undertaker was victorious. For the next few months, Mankind would ambush and cost the Undertaker several matches. The Undertaker faced Mankind for the very first time at the 1996 King of the Ring.

The Undertaker's feud with Mankind grew more intense. They began taking their battles into crowds and backstage areas. The two also fought in the boiler room areas of different arenas. As a result, these events lead up to the first ever Boiler Room Brawl match between the two at SummerSlam 1996. Undertaker nearly won the match by using the ropes to fling Mankind off the edge of the ring apron. However, when Undertaker reached for the urn, Bearer hit him with it, turning on the Undertaker and allowing Mankind to incapacitate the Undertaker with the Mandible Claw, giving him the win.

The Undertaker's feud continued with Mankind at In Your House: Buried Alive. This event marked the debut of the Buried Alive match, in which Undertaker defeated Mankind. The match also introduced The Executioner, who attacked Undertaker after the match. The In Your House: It's Time event saw the end of the feud with Mankind and The Executioner with a victory for the Undertaker over the Executioner.