Definition 2a seems related: "Producing [...] remarkable results, like those attributed to magic [...]; effecting or permitting change, success, etc., as if by magic."

Also the 'magic box'.

The Urban Dictionary (the place where I look for colloquialisms) has this definition: "with or through complexity either spurios to the contemproary context or to long to be reasonable or desired of explanation". [1]

1: http://www.urbandictionary.com/define.php?term=magic&defid=9...