Pulsar Grenade Arm

The description says "Supremely Devastating". This is only partially correct.

This weapon imprecisely fires an initial projectile that, upon impact with a target or solid block (or after traveling for about 3 seconds, whichever happens first), destroys nearby blocks in a 15-tile explosion AND splits into up to 16 tightly-clustered red-white fireballs. The fireballs will, in turn, also explode after a second or two destroying more blocks within a radius. This weapon can lag the game slightly whenever used.

The initial projectile can deal a moderate damage to enemies IF it makes a direct hit, but this is difficult because the initial projectile can have up to 15 degrees (or so) of inaccuracy, making the initial projectile useless against small targets (moving or not). The fireballs apply very strong knockback to nearby entities, but very little damage. (Presumably, entities so thrown in gravity environments might be able to take subsequent fall damage, but fall damage does not exist in zero-gravity environments where a mech is more likely to operate.) The fireballs will apply strong knockback (but not damage) to the user.

Blocks broken by this weapon are erased, not dropped. Pulsar Grenade Arms should absolutely not be used to mine valuable materials.

Overall, while this weapon can punch big holes in terrain, it has a hard time actually killing enemies.