Colon baby
When one takes such a massive dump that all the crap, along with air, leaves with such force that it creates a super vacuum. This results in the colon and/or other organs being shat out, or "given birth" to.
"Oh my god, call 911, I just had a colon baby."
Colon Baby
When anally injected semen leaks into the vagina and impregnates a woman. The child comes out with a noticeably darker skin tone.
"Man, that bitch thought she was being safe taking it up the ass but bitch got a colon baby."