automagically /aw-toh-maj'i-klee/ adv.
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. See
magic. "The C-INTERCAL compiler
generates C, then automagically invokes cc(1) to
produce an executable."
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.