Crayon Shinchan has a table with a quilt on it, which seems to be a heater. Yes, what's that?

Warm table (also called quilt, Japanese: torch, こたつ) is a Japanese heating appliance. The modern warm table is a square low table with a quilt above and an electric heater below, which is usually embedded in the table structure. The warm table is placed on a thin mat. You sit on the mat and put your legs and feet and even your whole body under the warm table to keep warm. When the weather gets warmer, you can take away the quilt and turn the warm table into an ordinary low table.