A thug threatened a shopkeeper with a hunting knife in a row over a pint of milk and told him: "I will gut you like a fish."
Kyle Hulme was jailed for eight months after a court heard how he also shouted foul-mouthed racial abuse at the victim.
Leeds Crown Court was told Hulme threatened the owner of Ferrybridge News and Booze on July 23 last year.
Hulme, 27, went into the store and took milk from the fridge before going to the counter.
Richard Canning, prosecuting, said the shop owner took the milk from Hulme and told him he would not serve him as he was banned over previous behaviour.
Hulme went back to the fridge and got some more milk, put his money on the counter and walked to the exit.
The shop owner stood in Hulme's way to stop him leaving.
Mr Canning said the two men argued for four minutes.
The prosecutor said: "During the conversation the defendant said he had got a blade."
Hulme then said: "My head has gone now - want to see it?"
The defendant unzipped his tracksuit top to reveal a large hunting knife inside a clear plastic bag.
Hulme left the shop and got on his bicycle but returned moments later.
He said to the victim "I will gut you like a fish" before swearing and and making a racially abusive comment.
Hulme, of Gannett Close, Castleford, pleaded guilty to possessing a bladed article and racially aggravated threatening behaviour.
Lucy Brown, mitigating, said Hulme was suffering from anxiety and depression at the time of the incident.
She said: "He simply went to make a purchase and was taken aback by the animosity he met in that shop."
"He said he had the knife because he had low thoughts of self harm."
Jailing Hulme, judge Tom Bayliss said: "Those who walk around our streets with a knife can expect no mercy from the court - not these days.
"Knives kill, knives maim, knives injure.
"If you take a decision to walk around our towns and cities with a knife you will go to prison I am afraid."