There are a plethora of synonyms for the phrase "work like a dog," each conveying the same sentiment of intense effort and dedication. One option might be "toil like a beast," which emphasizes the hard work and laborious nature of the task at hand. Alternatively, one could say "grind like a millstone," which invokes the image of a heavy stone grinding against grain with unyielding force. Another option might be "hustle like a champ," which embraces the idea of striving for greatness and putting in maximum effort to achieve success. Whatever the phrasing, the underlying implication is clear: when faced with a challenging goal, working tirelessly and relentlessly is the key to achieving success.