Colin the Caterpillar is a staple of Marks & Spencer and just like Percy Pig, any variation of the branded product causes a frenzy.
But now, M&S want Aldi to remove its copy-cat of its popular Colin the Caterpillar cake from sale.
The company has started legal action against the budget supermarket with a claim that its rival's Cuthbert the Caterpillar product infringes its trademark.
M&S, which lodged an intellectual property claim with the High Court this week, is arguing that the similarity of Aldi’s product leads consumers to believe they are of the same standard.
It also claim it "ride on the coat-tails" of M&S’s reputation with the product.
Therefore, M&S wants Aldi to remove the product from sale and agree not to sell anything similar in the future.
A spokesman said: "Because we know the M&S brand is special to our customers and they expect only the very best from us, love and care goes into every M&S product on our shelves.
"So we want to protect Colin, Connie and our reputation for freshness, quality, innovation and value."
M&S launched the chocolatey Colin the Caterpillar treat more than 30 years ago and has recently been adapted for different occasions such as Christmas and Easter.
And it's also more than just the cake with jelly sweets, chocolate Colin faces and other products making up the ever-growing collection.
M&S has three trademarks relating to Colin, which the retailer believes means Colin has acquired and retains an enhanced distinctive character and reputation.
