If you mean the Philidor Counter Gambit, it's not that dangerous if white has some knowledge. A lot of fun, though.
Philidor or Leviathan
Sort:
the leviathan Gambit
1-e4 e5 2-Nf3 f5
the frensh Philidor had adopt this opening against the syrian Stamma
1- e4 e5 2-Nf3 d6 3-d4 ...
Morphy enjoys ... f5 which could be a transposition of the leviathan Gambit one of most dangerous gambits