DETROIT -- Darius Slay turned around and couldn’t believe what he thought he might be seeing.

In the second quarter, the Detroit Lions cornerback was defending Chicago tight end Martellus Bennett in the end zone when he felt something hit his leg and it wasn’t a player.

“I’m looking at it like, ‘Did somebody just throw a bottle at me,’ “ Slay said. “I looked back like, ‘What’s going on?’ But I felt it. I looked, like I’m looking around.”

What was actually thrown from the stands in Ford Field is up for debate. Slay said it was a bottle. Bennett said he thought it was either a "spray can” or “air horn” tossed from the crowd.

Bennett saw it coming, too.

“It was like one of those (air) horns or something,” Bennett said. “I saw it coming and the DB saw it, too. He was like, ‘What the [expletive]?’ “

This is a particularly tense issue in Detroit, where a drink thrown from the stands at the Palace of Auburn Hills in 2004 ignited a brawl between the rival Detroit Pistons, Indiana Pacers and fans.

This was another rivalry game in a different sport, but there was no brawl this time -- just a couple of confused and annoyed players.

“I was just kind of mad,” Slay said. “Because it was, ‘Who just threw a bottle at me?’ “

NFL Nation Bears reporter Michael C. Wright contributed to this report.