heard of anything like this before, is this freaky or something common that I've just
never heard of?

It's called "vivipary", and it's not uncommon in tomato and citrus.
See, for instance:

http://www.uky.edu/Ag/Horticulture/2000/hhh300.htm
http://www.css.cornell.edu/seedbio/dorm9.htm
http://www.plantphysiol.org/cgi/content/full/122/4/1081