The Rain Frogs.

Breviceps, or more commonly known as, the 'rain frogs' are a species of burrowing frogs that can be found in Eastern and South Africa. Rain Frogs are a burrowing species and spend more than half of their time burrowed deep under the ground. Even when they emerge shortly after rain, they're slow moving and barely hop!

There are currently twenty different species documented :

One of the many reasons these ambphibions blew up was due to the squeaky sound they make rather than a typical croak. Rain frogs are known for their frowning faces and round bodies and have gone viral in the past for the adorable appearance. Anastasia Arellano, author of an article for The Rainforest Site had this to say about their apperance-
"Perhaps the cutest thing about the frog’s appearance is that it resembles an upset avocado. He’s not actually sad, that’s just the frog’s natural face."
Desert rain frog
Like many of the other wildlife in the world, the rain frog is currently at risk of being an endangered species. If you have any information or are curious to learn more, you can send an email toWWF or head to the World Wildlife Organization website.