Question: Old Central's bell clapper was considered a trophy in which rivalry between Oklahoma and Oklahoma State?

Context paragraphs:
Campanile symbolicum: Campanile symbolicum, common name the bell clapper or the giant creeper, is a species of large sea snail, a marine gastropod mollusc in the family Campanilidae.

Oklahoma State University–Oklahoma City: Oklahoma State University–Oklahoma City (abbreviated OSU-OKC) is a coeducational public university located in Oklahoma City, Oklahoma.  Originally a branch of Oklahoma State University–Stillwater beginning in 1961, its name changed from Oklahoma State University Technical Institute to its current designation in 1990.  It is part of the Oklahoma State University System.  The school offers more than 40 degrees and/or certificates.  Traditional semester classes are held weekdays and weeknights, with three-week session classes available on the weekends.

Bedlam Series: The Bedlam Series refers to the athletics rivalry between the University of Oklahoma Sooners and the Oklahoma State University Cowboys of the Big 12 Conference.  Both schools were also members of the Big 8 Conference before the formation of the Big 12 Conference in 1996, and both were divisional rivals in the Big 12 South Division prior to 2011.

Old Central: Old Central is the oldest building on the Oklahoma State University campus in Stillwater, Oklahoma.  Originally built in 1894, it was the first permanent building on the Oklahoma A&M campus.  Old Central's bell clapper once served as a traveling trophy in the Bedlam Series athletics rivalry between Oklahoma State University and the University of Oklahoma.  The new "Bedlam Bell" is a crystal trophy modeled after Old Central's bell and is awarded to the winner of each individual athletics contest in addition to the overall series winner for each year.

Red River Rivalry trophies: There are three Red River Rivalry trophies given to the winner of the annual Red River Rivalry (previously Red River Shootout) which is a college football rivalry game between The University of Texas Longhorns and the University of Oklahoma Sooners.  The trophies are the Golden Hat, the Red River Rivalry trophy and the Governors' trophy.  The trophies reward the annual winner of one of college football's longest and most intense rivalries.  2005 marked the 100th meeting of the two football programs.  The rivalry began in 1900 while Oklahoma was still a territory of the United States.  In the first 100 games of the rivalry, Texas won 56 times to 39 Oklahoma victories and 5 ties.  The 2007 match-up between Oklahoma and Texas was predicted to be the #3 game to watch in 2007 by SI.com's "Top 20 Games To Watch In 2007" list.

Oklahoma State University System: The Oklahoma State University System is a university system comprising six educational institutes across Oklahoma: four general academic universities and two health institutions.  Its flagship institute is the Oklahoma State University–Stillwater.  The Oklahoma State University System has a total enrollment of about 35,073 students and is the largest university in the state of Oklahoma.  It is governed by the Oklahoma Agricultural and Mechanical Colleges Board of Regents in Oklahoma City, Oklahoma.  The System also has Agricultural Experiment Stations throughout Oklahoma and Cooperative Extension offices that serve all 77 counties.  V. Burns Hargis currently serves as CEO of the Oklahoma State University System, in addition to his service as president of OSU-Stillwater.

1987 Oklahoma State Cowboys football team: The 1987 Oklahoma State Cowboys football team represented the Oklahoma State University in the 1987 NCAA Division I-A college football season.  The Cowboys finished the regular season with a 9–2 record.  Thurman Thomas was in his senior year for the Cowboys.  In his career at Oklahoma State, Thomas had 897 rushes for 4,595 yards, 43 touchdowns, and 21 100-yard rushing games.  He also a Heisman Trophy candidate and a first team selection on the College Football All-America Team in 1987.  In the 1987 Sun Bowl, Thomas ran for 157 yards and four touchdowns in the 35–33 victory over West Virginia, keeping Barry Sanders on the sidelines for the majority of the game.  Thomas left OSU as the school's all-time leading rusher and his number 34 is one of only three jerseys retired at Oklahoma State.  Sanders replaced Thomas as starter the next year in 1988.

Whimbling iron: A whimbling iron is a bell clapper made from ductile iron.  Traditionally bell clappers were standard cast grey iron with a razor-like crystalline structure that led to sudden catastrophic failure over time.  The standard clapper is distinguished by the experienced ear as a whefting iron.  Whilst some believe that the advent of "health and safety" led to the search for an alternative, it is more likely that the ability to forge the bottom end ready for use practically died out early in World War II.  Some attempts at composite clappers were made, but advances in casting technology, driven as much by the motor industry as by the war, resulted in the adoption of spheroidal graphite iron castings.

Oklahoma State–Tulsa football rivalry: The Oklahoma State–Tulsa football rivalry, also known as the Bank of Oklahoma Turnpike Classic, is an American college football rivalry between the Oklahoma State Cowboys and Tulsa Golden Hurricane.  From 1935–1956, the two teams both competed in the Missouri Valley Conference.  In those 22 seasons, the conference champion would be won by either Oklahoma State or Tulsa 16 times, thus establishing a rivalry.  They played each other annually from 1926–1965.  The two universities are an hour apart from each other.

Franklin bells: Franklin bells (also known as Gordon’s Bells or lightning bells) are an early demonstration of electric charge designed to work with a Leyden jar.  Franklin bells are only a qualitative indicator of electric charge and were used for simple demonstrations rather than research.  This was the first device that converted electrical energy into mechanical energy in the form of continuous mechanical motion, in this case, the moving of a bell clapper back and forth between two oppositely charged bells.

Supporting paragraphs: Old Central Bedlam Series
Answer: Bedlam Series