"This is not good news."
Garen Muln[src]

The Merr-Sonn mobile grenade mortar was an assault vehicle used by the Galactic Empire. It was capable of firing a total of approximately one hundred grenades per second, with storage for hundreds more grenades that could be reloaded through a tube. It was operated by two stormtroopers on a repulsorlift sled; the vehicle could accelerate fast and rise up in the air up to thirty meters.

In 19 BBY, two former Jedi, Ferus Olin and Garen Muln, were attacked in the Crystal Caves by thirty stormtroopers and a Merr-Sonn mobile grenade mortar.