Howdy, @soundexcess! I’m not the artist so I can’t comment on his inspiration, but I can at least provide a little bit of context about the contest and what some elements in the design may be referring to.
Do512.com and SXSW are both based in Austin, Texas. Austin is frequently shortened to it’s nickname ATX, and is famous for the migrating colony of Mexican free-tailed bats that make their home under the Congress Ave bridge. My best guess is that since the theme of the design contest was “The BIG One,” this artist featured a giant bat-like creature with a “1” (aka- the big “one”) in its forehead, looming over the Texas Capitol building which looks over the Congress Ave bridge, and titled the design BIGBATX (Big + Bat + ATX). Not sure if that helps much, but I hope it helps clarify things a little. Thanks for participating in the forums!