The Catapult is a second-line Heavy support BattleMech designed to deploy missiles at long ranges while staying safe from return fire.
Produced on behalf of the Terran Hegemony in 2561, the Catapult was the first BattleMech designed by Hollis Incorporated. Designed as all-terrain artillery support, the Catapults were recalled as early as 2566 due to shitty jump jets used in its design. For some bizarre reason Hollis Inc opted for a sideways ejection system instead of the traditional upwards. Though it reduces the risk of landing on the wrecked remains of your own 'Mech, it will send you tumbling asscheeks-over-facecheeks when your capsule hits the ground.
The Catapult remained popular for a long time: near the end of the Succession Wars it was often paired with the Raven Electronic Warfare BattleMech to great effect, despite there being almost five centuries between the two 'Mechs. This partnership lasted well into the Clan Invasion.
The Catapult is one of the machines the Mad Cat derived its name from, with its conical cockpit, large shoulder-mounted missile launchers and large grabby feet.
The primary weapons of the Catapult are its large LRM-15s, allowing for deadly bombardments at very long ranges. While protected from enemy fire, the nature of a missile platform like the Catapult meant it could not stray far from supply lines without risking running out of missiles.
While not meant for shot-range engagements, the Catapult has four Medium Lasers build into its torso to defend itself against any attackers that come too close. Though effective against smaller 'Mechs that make likely candidates to actually fight a Catapult (scout 'Mechs), against models of its own size (65 tons) it would only delay the inevitable.
Putting the "Miss" into "Missile"
While many variants of the Catapult were made, they often did not differ all that much from the "missile-platform-with-legs" school of thought. A number of them include systems that improve the function of the missile launchers, such as the C2 model and its Artemis IV Fire Control System (an infrared targeter).
There are a few odd designs out: the C6 model spots a pair of Plasma Rifles, and the K2, K2k, K3 and K4 models that spotted various different kinds of PPCs making the Catapult a direct fire support unit.