ffmpeg -i benny_lava.avi -s 72x54 -t 14 -r 25 -pix_fmt rgb24 benny_lava.gif
The problem is that somehow the GIF ends up being 7 seconds instead of the original clip's 14; thus, double the speed.

Also, how does the GIF, which is much smaller in frame size than the ~650KB AVI and without audio, end up at 1.5MB?