PUZZLER
puzzle, puzzler, mystifier, teaser
(noun) a particularly baffling problem that is said to have a correct solution; “he loved to solve chessmate puzzles”; “that’s a real puzzler”
Source: WordNet® 3.1
Etymology
Noun
puzzler (plural puzzlers)
A puzzling situation or problem; an enigma.
(video games) A video game in which the player is presented with (usually abstract) puzzles to solve.
One who solves puzzles as a hobby.
Source: Wiktionary
Puz"zler, n.
Definition: One who, or that which, puzzles or perplexes.
Hebrew, the general puzzler of old heads. Brome.
Source: Webster’s Unabridged Dictionary 1913 Edition