iThe bunny is a the macot of Nesquick, a product line of Nestlé.
The original slogan is if I can shoot rabbits, then I can shoot fascists attributed to a remark made by a British man who signed up with the Republican fighters in the Spanish Civil War. This was originally quoted in the book Miners Against Fascism by Hywel Francis. The slogan was meade famous by Manic Street Preachers' song If You Tolerate This Your Children Will Be Next.
