The tweet in question from the account @IntThings
Meet the Teletubbies
It's "Tubby Custard"!
Here is the official page for it
"Tubby Custard" in action
This is what mechanically separated chicken actually looks like...
The moral of this story?
Don't believe everything you hear on the internet, this is a pretty funny mix up (considering mechanically separated chicken actually looks like this) and it may have been intentional because the original image posted on Twitter came from a tubby toast Tumblr post. Either way, this Twitter account has hundreds of people believing that this in in their food.