 The knocker or bucca (Cornish) is the Welsh and Cornish equivalent of Irish leprechauns and English and Scottish brownies.About two feet tall and grizzled, but not misshapen, they live beneath the ground.Here they wear tiny versions of standard miner's garb and commit random mischief, such as stealing a miner's unattended tools and food - they were often cast a small offering of food – usually the crust of a pasty – to appease their malevolence.