Milkybar
Cheerios is a breakfast cereal owned by Nestle.
The owner of the Cheerios brand, Nestle, owns a controlling stake in Osem. Osem is an Israeli food manufacturer which operates in Occupied Palestine.
Don't buy Cheerios products
Avoid Nestle products until they divest all operations in Occupied Palestine.
Especially avoid any Osem brands such as Sabra and others which can be found via the wikipedia page in the source.