The new vegan Imposter Burger officially sold out in four days since launching at Kentucky Fried Chicken (KFC) restaurants in the United Kingdom. On June 17, KFC launched the vegan burger—made with a specially formulated Quorn patty and served with vegan mayonnaise—at select UK outposts with the intent to test the menu item until July 15. The Imposter Burger—which will return on July 2—proved popular and pulled in 500 percent more in sales than any other new product launch at KFC. “We knew there were plenty of people who would want to get a taste of the Imposter, but we didn’t anticipate this phenomenal response,” Victoria Robertson, Senior Innovation Leader at KFC, told Metro UK. KFC’s vegan burger follows a trend experienced by other major chains after launching a new vegan option. Last summer, A&W launched the Beyond Burger at its 925 locations in Canada, which sold 90,000 vegan burgers in 72 hours. At Del Taco in the United States, the launch of Beyond Tacos in April resulted in nearly two million purchases of the vegan-friendly menu item—one of the most successful new product launches at Del Taco to date—and inspired the chain to expand its partnership with Beyond Meat to include two new burritos, one stuffed with crinkle-cut fries. Burger King had a similar experience when it launched the Impossible Whopper at 59 locations in St. Louis, MO earlier this year, where foot traffic increased by 18.5 percent over other outlets that did not offer the plant-based burger.