A hideously ugly baby, with usually good looking parents, who when you first lay eyes on it, causes your brain to make the high pitched squealing noise oft associated with bat sonar. Sometimes bat baby's may have wings or pointy fang like teeth.
The super model couple down the street just got back from the hospital......you should see the bat baby they brought back; it'll make your brain explode.
by Deering September 13, 2006
by trippypoet September 16, 2018