Halasz-McDonnell Gambit, Crocodile Variation

The Crocodile Variation arises when Black meets the Halasz-McDonnell Gambit with 3...Bc5 and White, after 4. Nf3 Nc6, plays 5. c3 to challenge the d4-pawn at once instead of leaving it to control c3. Removing it would free that square for a knight guarding e4. Black usually captures with 5...dxc3, and 5...d5 is a strong alternative. Engines judge Black clearly better, and Black wins more often in practice. The rare 5...d3 has fared poorly.