Friday, students from the Mirus Academy in Katy were heading to the Holocaust Museum when they saw the spool.
"We're talking and we look outside and there was a big blue thing rolling down the highway and went from the left side to the right side," a student named Sydney told KTRK.
"When you're taking a group of students, you don't expect a Ferris wheel to come right at you," Principal Laura Hogan, who captured some of the incident on her cell phone, told the television station.
"The bus driver let out a loud 'yelp' and started to slam on the brakes," Hogan told KTRK. "I thought we were about to get in a wreck, so I braced myself and looked up about to see a wreck going to happen, but what I saw was a gigantic spool."
The truck driver was cited, the television station reported. There were no injuries.