Halifax raced three goals up after half an hour to maintain their 100% home record by steamrolling Grimsby.
Marcus Carver headed in Adam Smith's cross to put the Shaymen ahead, before Dan Gardner hit a second soon after.
Smith was the provider again, playing Gardner in to all but seal victory with just 32 minutes on the clock.
Two minutes after the break, any hope of a Mariners fightback disappeared when Smith struck to inflict Grimsby's fourth consecutive away defeat.
VIEW FROM THE CHANGING ROOM
Grimsby Town boss Paul Hurst told BBC Radio Humberside:
"I wouldn't say painful, I'd say embarrassing was more a word that I would probably use.
"As daft as it sounds I don't see how we don't get on the scoresheet but that's the least of our worries - but at least that would have given us something for the second half.
"The amount of times we're running back to our goal but the wrong side, I lost count and at the minute it's a little bit of a blur in terms of how each goal came about.
"We've had more than enough of the ball but we know we have to do more with it."