1881 Large Cent

Actually the spur doesn't head "both ways" All 1881 working dies started out as 1876(Single serif N's) partially completed die blanks and then the N's were handpunched to make them full serifs. A spur going both ways is just a low/high handpunch of the N, the first punch being way off. There are any number of truely mangled N's in the 1881's. The one going both ways is much more common than the spur.