What is the weakest extinct animal that could beat 100 unarmed men on land?

I say extinct because realistically no modern animal is doing it

R1: They are trapped in a roman colisseum style arena

R2: Open field

I think it would be something like a large theropod or maybe hadrosaur, dinosaurs had more efficient lungs than mammals so they would negate the stamina advantage (you can see this with ostriches today). One of the giant extinct elephants might be able to take it as well.