Why exactly? Well, many Brits think they know what is to blame for the sudden change: Brexit.
Whether the new shape can be entirely blamed on Britain's decision to leave the European Union isn't clear. The vote in June to leave the E.U. sent the British pound falling amid uncertainty about the country's political and economic future, prompting some food producers to announce plans to raise prices.
Last month, Britons were upset to discover that supermarkets were running out of the nation's favorite condiment — the love-it-or-hate-it Marmite — because of a pricing dispute in the wake of the Brexit vote. While that dispute was eventually solved, many viewed it as a sign of worse to come.
On Oct. 15, Toblerone first announced its plan to change the shape of some of its chocolate bars. In a statement posted to the candy bar's official Facebook page, the new shape was blamed on “higher costs for numerous ingredients.” Brexit was not mentioned specifically.
However, it was only in the past few days that the decision gained widespread attention, with social media users voicing outrage.
Toblerone has a special place in Britain's confectionery culture, with travelers to Europe traditionally bringing the bars back home as gifts for friends and family. To many, the new Toblerone bars signal a dim economic future for Britain outside the E.U.
Some used the controversy over the chocolate bar to comment on the U.S. presidential election on Tuesday.
Despite the widespread speculation, Mondelez officials told the Wall Street Journal on Monday that the change had been planned long before the Brexit referendum. The company had already reduced the size of one Toblerone bar sold worldwide from 400 grams to 360 grams (about 14 oz to about 12.7 oz).
Ironically, although the company cites cost concerns as the reason for the shape change, one of the bars that will have its shape altered — a 170-gram bar that is dropping to 150 grams — is largely sold at Britain's Poundland chain of budget stores.