The Bump in the Night Originals Pack, which includes The Fiend Bray Wyatt, is a bonus for pre-ordering WWE 2K20 and is also available for individual purchase as DLC. Bump in the Night is a horror-themed pack featuring a unique 2K Showcase, 2K Towers, spooky versions of various WWE Superstars, and three new arenas.
To harness the chaotic power of The Fiend Bray Wyatt, you will first need to play and complete the "Fear is Power" tower available in-game through 2K Originals, then selecting Bump in the Night. After that, all you have to do is…let him in.
For further information on how to install DLC, check out this help article: https://support.2k.com/hc//articles/360033674094-How-Do-I-Install-Additional-Content-DLC-