defines something that happens automatically but you can't quite explain how it happens or the explanation is too complex.

Also, can be used as "automagically".

1. adj, a task/activity that is so complex or so boring/uncomfortable that one doesn't feel like explaining it or bothering to look up how it works.

2. when something just happens

A common slang word for "automatic". Often used in webblogs and other forms of internet communication.

A technology that works but is too complicated to explain or understand

Automatically, but in a way that, for some reason (typically because it is too complicated, or too ugly, or perhaps even too trivial), the speaker doesn't feel like explaining to you.

This term is quite old, going back at least to the mid-70s in jargon and probably much earlier. The word `automagic' occurred in advertising (for a shirt-ironing gadget) as far back as the late 1940s.

adv. Something that happens automatically, but that also has some mysterious, "magical" element to it. "Smart" appliances, features, etc. that do intelligent things with less help than you might expect.

A mechanical painball marker manufactured by Airgun Designs(AGD).
The Automag, along with the Autococker, were the premiere markers back in the mid 90's. The widespread acceptance of electronic guns resulted in the Mag's decline.
However, due to it's quality and reliability, the Automag still retains a small but loyal following.