Gerasecian 21 cm Mörser 18

"The Gerasecian version of a 21 cm Mörser 18 seems to be upgraded to be able to fire high-explosive shells and/or mustard gas ammunition so they can assault and/or siege at enemy forces to support Gerasecian troopers while they were damaging Canterlot Castle. Since Twilight Sparkle failed to protect Ponyville and Princesses Celestia and Luna went back to ruling Equestria, I bet things are gettin' much worse with this."

--Su Ji-Hoon, The Hathorians

The Gerasecian 21 cm Mörser 18 is the Gerasecian heavy howitzer of the Federal Army of Gerasecia that it was the Gerasecian version of 21 cm Mörser 18

It would be built in during the Battle of Canterlot that it would be used for attacking at the Equestrian troops and siege at Equestrian bases. It also to trying damage Canterlot Castle

Later,it would fire either howitzer ammunition or mustard gas ammunition to assault or siege at enemies for each support Gerasecian troops