Why is Halloween significant in KU's football history?

Ooh, this is a good one. On October 31st, 1891, KU's most heated rivalry was born. We played MU and BEAT THEM 22 to 8. We've played each other well over 100 times since then. The rivalry is the oldest West of the Mississippi River. The KU and Big 12 records have the score at 55-55-9. MU has the record listed in their favor at 56-54-9. Halloween is also important due to Missouri announcing their departure from the Big 12 to the SEC on October 31st, 2011.