The Siege Onager is the final upgrade of the Mangonel Line of grapeshot-firing catapults. It has a greater splash radius and attack, and deals more damage, but does not fire any further. The Siege Onager is only available to a few civs.
Built at: Siege Workshop
Cost: 160 Wood, 135 Florins, 3 population slots
Armor/Pierce Armor: 0/13
Range: 10 (MR 3)
Special: +60 vs. buildings, +12 vs. siege weapons.