WWE's Undertaker Retires ... Leaves Gear In Ring After WrestleMania

The Undertaker apparently put the final nail in his pro wrestling coffin Sunday night ... leaving his gear in the ring after his match with Roman Reigns at WrestleMania.

The 52-year-old WWE legend had just lost in the main event when he removed his signature hat, gloves and coat ... and then waved at the fans.

The move is a traditional way of signifying retirement among wrestlers ... and while there has been no official retirement announcement, the message seems pretty clear.

R.I.P.