Pronouced: "What the bear"
Derivation of wtf
and is an expression used to illustrate surprise and slight confusion.
History of the word comes from older Quake 1 days (1996-97) in which it became common lingo on the internet to say ombear instead of omg (thus bear replacing God for those who praise the bear). Adding Bear to words became popular and quickly afterwards, "bear" replaced the "f" in wtf and this is how "wtbear" was born.