Had to be a Malinois. Those guys are nuts.
I have a Tervuren, which is the long-haired, hippy version of the Malinois. He was a Katrina rescue and I took him in when he was about 18 months old. When he was younger, he had a degree of wanderlust, and appetite for cats and for about the first year I had him, terrible separation anxiety which manifested by him chewing things. I lost several remote controls, a number of art projects, but the worst was the bottle of green leather dye which left a stained carpet and a dog with an olive tongue for about a week...
He has mellowed nicely in his old age and is curled up at my feet as I type this.