Squeaky cheese, a.k.a. cheese curds, are the very fresh curds of cheddar cheese, before they’ve been gathered in a mold and pressed. Squeaky cheese looks sort of like irregular packing peanuts. Fresh ones squeak when you chew them.
They’re used in the popular Quebec dish poutine, which is french fries and cheese curds doused with gravy. Cheese curds are also popular in Wisconsin. You can fry them, like mozarella sticks.
Read about cheese curds.