Ironhide Bulls were 4th-tier magic beasts due to their iron-like hide and violent nature. They were very aggressive creatures, and would often attack unprovoked, making them one of the most troublesome magic beasts for hunters and mercenaries to deal with.
The Ironhide Bull had powerful defensive properties, so killing one would take a very long time. However, compared to other 4th-tier magic beasts, it had no valuable body parts aside from its flesh and hide, so it had a very low benefit-to-cost ratio.
And yet, there was an Ironhide Bull strapped to the metal bench, causing the bench to shake violently along with its vehement struggles. Mag's eyelids twitched upon seeing that, and he was worried whether the bull would be able to struggle free from its bindings. It would be very difficult to evade such a huge creature in such a small space.