'Face-eating leopards' is a popular way to refer to political parties and policies that restrict people's freedoms. It is most often used sarcastically, especially to mock people who voted for a policy in hopes it would benefit them, and then found that it harmed them.
While the formulation 'face-eating leopard' seems to be the current favorite, 'leopards eating people’s faces' is also popular, and is in fact the original form, as coined in a tweet by author Adrian Bott:
'I never thought leopards would eat MY face,' sobs woman who voted for the Leopards Eating People's Faces Party.
-- Twitter.com, by Adrian Bott @Cavalorn, 16 Oct 2015
This tweet was posted shortly before the Brexit referendum, and took off just in time to ride that wave. The meme did not spread across the Atlantic quickly enough to participate significantly during the 2016 US elections, but was well established by 2018. Currently most of the people refering to leopards are firmly anti-Brexit or anti-Trump, but I suspect that the phrase may outlast these troubles and come to refer to any downsides of the policies of the party in power.
"Once the biggest face-eating leopard goes away, the rest of the face-eating leopards will become herbivores." - Joe Biden.
-- No, not actually Joe Biden; actually @jkyles10 , Jun 10, 2019