There are two possibilitis I can think of:
It could be a one-piece (or 'American') crankarm bottom bracket commonly found on kid's bikes, BMXs, and department store bikes.
Or it could be some uncommon obsolete design, such as what (I think) Fisher used in the mid-late eighties.
If it is for a one-piece crank, you can get replacement parts through any LBS, or get another $5 and scavnge the parts you need.
If it is some other crazy concept BB like a Fisher or something from the days of yore... good luck!