Michael Geiger's walk-off 41-yard field goal upset No. 2 Ohio State in Columbus in 2015

A shocking college football result can mean different things to different people. 

To me, it's both an unexpected outcome and a wildly disparate margin in a game of seemingly-mismatched opponents. 

Hence, I accord OSU's 55-24 loss to Iowa on Saturday as an Old Sparky sort of shocker, the kind that's a once-in-a-lifetime heart-stopper. 

Ohio State doesn't lose very often, so Buckeye defeats are as easy to remember as they are hard to stomach. 

This is my list of the Ten Most Shocking Ohio State Football Defeats of the last 50 years, all of which are more-indelibly etched in my mind than any Halloween horror show. 

No. 10: Indiana 31, Ohio State 10 

    Date: 10-10-87 at Ohio Stadium. 

    Shock value: OSU entered 4-0-1 and ranked ninth two weeks after a 13-13 tie at LSU. The Buckeyes hadn't lost to Indiana in 51 years, but former OSU assistant coach Bill Mallory's Hoosiers pounded out a three-touchdown victory that defeated coach Earle Bruce termed, "the darkest day  in Ohio State football history." 

No. 9: Michigan State 17, Ohio State 14 

    Date: 11-21-15 at Ohio Stadium. 

    Shock value: The No. 3 Buckeyes started the season atop the polls as the only unanimous No. 1 team in history. But after a series of so-so performances, fell two spots in the rankings. Still, no one saw imminent danger with a stocked roster featuring five eventual first-round NFL draft choices and a record number of picks in the first four rounds. Michigan State, despite its No. 9 ranking, figured to fold when quarterback Connor Cook went down with an injury the week before. Instead, backup quarterback Tyler O'Connor, of Lima, did just enough and kicker Michael Geiger's 41-yard field goal on the final play handed perhaps the best Ohio State team ever a loss that kept it out of the College Football Playoff. 

No. 8: Michigan 28, Ohio State 0 

    Date: 11-20-93, Michigan Stadium. 

    Shock value: Six years into the John Cooper era, the Buckeyes appeared to be rolling toward the Rose Bowl, unbeaten at 9-0-1 and ranked fifth. Michigan was just 6-4 and unranked, but intercepted Bob Hoying and Bret Powers four times to shockingly shut out OSU. A week later, Wisconsin beat Michigan State in Tokyo and the Badgers were bound for Pasadena, relegating OSU to the Holiday Bowl. 

No. 7: Purdue 26, Ohio State 18 

    Date: 10-17-09, Ross-Ade Stadium. 

    Shock value: No. 7 OSU had recovered from an early-season, three-point home loss to USC and figured to roll against Purdue, which had lost five straight after a win in the season-opener. Instead, the Buckeyes sleep-walked through its first loss to a sub.-500 team in eight years, a defeat made all the more inexplicable by an eventual victory over Oregon in the Rose Bowl. 

No. 6: Michigan 24, Ohio State 12 

    Date: 11-22-69, Michigan Stadium 

    Shock value: No. 1 Ohio State needed only to triumph in Ann Arbor to sew up a second straight unbeaten season and defend its national championship from 1968. No. 12 Michigan, under first-year coach Bo Schembechler, avenged a 50-14 loss to OSU the year before by scoring all its points in the first half and shutting out the Buckeyes thereafter to land the first blow in the Ten-Year War. 

No. 5:  Florida 41, Ohio State 14 

    Date: 1-8-07, University of Phoenix Stadium. 

    Shock value: Unbeaten and No. 1 Ohio State rolled into the BCS championship game with Heisman Trophy winner Troy Smith at the controls of an offense that survived a No. 1 vs. No. 2 matchup against Michigan in the regular-season finale. But the Buckeyes' offense didn't make the trip in from the parking lot, managing only 82 yards total offense against the Gators and then-head coach Urban Meyer. Florida defensive ends Derrick Harvey and Jarvis Moss wreaked havoc all night after OSU's Ted Ginn Jr. returned the opening kickoff for a touchdown and sprained his ankle in the post-score celebration in the end zone, thus rendering him unable to play thereafter. 

No. 4: Illinois 28, Ohio State 21 

    Date: 11-10-07, Ohio Stadium. 

    Shock value: After the loss to Florida the previous season, Ohio State rang off 10 consecutive wins to move from No. 11 to No. 1 in the polls. A return to the BCS title game seemed assured, but unranked Illinois stunned a Senior Day crowd in the Horseshoe with quarterback Juice Williams running quarterback draw after quarterback draw to knock the Buckeyes off course. A string of subsequent upsets over the remaining two weeks pushed OSU back atop the BCS rankings, but LSU ended those title dreams with a 38-28 win in the Sugar Bowl. 

No. 3: Michigan State 28, Ohio State 24 

    Date: 11-7-98, Ohio Stadium. 

    Shock value: No opponent had come within two touchdowns of unbeaten and No. 1 OSU all season in the first year of the BCS. Michigan State seemed unlikely to change that, given its 4-4 record, and a 73-yard Damon Moore interception return for a touchdown that handed the Buckeyes a 24-9 lead midway through the third quarter. But three of OSU's five turnovers in the time that remained helped MSU score 19 unanswered points to knock OSU out of both the national championship game and the Rose Bowl. 

No. 2: UCLA 23, Ohio State 10 

    Date: 1-1-1976, Rose Bowl. 

    Shock value: A 21-14 victory at No. 4 Michigan in the regular-season finale kept OSU atop the polls and seemed to foreshadow a national championship in what would be two-time Heisman Trophy winner Archie Griffin's final game. After all, Griffin and the Buckeyes already owned a 41-20 victory over UCLA in Los Angeles earlier in the season on Oct. 4. But the Bruins held OSU to just a field goal in a first half the Buckeyes dominated, and receiver Wally Henry and tailback Wendell Tyler scored second-half touchdowns to hand Woody Hayes one of his most crushing defeats ever in his final trip to Pasadena. 

No. 1: Iowa, 55, OSU 24 

    Date: 11-4-17, Kinnick Stadium. 

    Shock value: Fresh off a pulsating, 39-38 home win over No. 2 Penn State, OSU looked to bolster its College Football Playoff credentials with a win over the offensively-challenged Hawkeyes. Iowa had managed only 10 points in a loss at Northwestern, and only 17 in a win over Minnesota, in its previous two games. But despite that, and a 5-3 overall record, Iowa gained strength from a J.T. Barrett pick-six on the first play and eviscerated the OSU defense thereafter to the tune of 487 offensive yards and the most points ever against an Urban Meyer-coached defense. 

Honorable mention: 

Stanford 27, Ohio State 17 (1971 Rose Bowl) 

Michigan 31, Ohio State 23 (11-25-95) 

Minnesota 29, Ohio State 17 (10-14-2000) 

Michigan State 19, Ohio State 12 (11-11-72) 

Virginia Tech 35, Ohio State 21 (9-6-14) 

PHOTO: GETTY IMAGES