This one never had lunch at a public school in the 80s/90s...

Also a common thing at mine, oranges cut to a size where you could put them in your mouth to wear like a boxing mouth guard. Called them orange smiles...

Depending on how old they are and where they grew up, my assumption would be the Pizza Hut Big Foot, a massive rectangular pizza that was roughly 1 foot by 2 feet, cut into squares

They were great, no clue why they stopped making them