The goal of any new product, in pretty much any industry, is to “surprise and delight” customers. When Lewis Road Creamery started selling its chocolate milk in northern New Zealand at the beginning of October, customers were definitely delighted—but it was the creamery that ended up most surprised.

Lewis Road Creamery was, until a few weeks ago, best known for its butter. Then the boutique New Zealand dairy company decided to do something new with its fresh milk products by partnering with Whittaker’s, a local confectioner, to create a chocolate drink. Each batch is made by melting Whittaker’s 5 Roll milk chocolate into fresh Lewis Road whole milk. The creamery started out making 1,000 liters per week, for sale in 750mL and 300mL bottles priced at NZ$6.49 and NZ$3.69, respectively. (That’s $5.10 US dollars or four euros, for the larger bottles.)

But 1,000 liters a week was nowhere near enough to meet demand; now Lewis Road—staffed by only five people, according to DairyReporter.com—is struggling to churn out 40 times that volume while Kiwis scramble to get their hands on the product. This is “the Kiwi equivalent of the Cronut,” according to one New Zealand media company.

As one satisfied customer, who apparently received two bottles of the milk as a gift, explained to her followers on Instagram: “Should be available in any local super markets, they just sell out really quickly. They are the new trend because they are made from the creamiest milk & best chocolate in New Zealand, and they have such a short supply.”

According to Euromonitor, the drinkable milk market in New Zealand is led by Fonterra, which happens to be the country’s largest company and the world’s largest dairy exporter; in 2013, Fonterra sold a limited edition milk made with Cadbury’s Pineapple Lump candies, which became very popular and perhaps paved the way for more drinkable milks mixed with candy, such as Lewis Road’s.

Lewis Road Creamery chocolate milk is so coveted by Kiwi consumers that some grocery stores have hired security guards to monitor hour-long lines for the milk, and others are limiting individual purchases to no more than two bottles per customer.

People are making their own versions at home, which a creamery spokesperson said is great—as long as they don’t bottle and sell it. Of course, counterfeit versions have hit the market anyway, in stores and on New Zealand’s eBay-like website trade.me.