Space Crusade Conversion Beamer and Las-Cannon

Mission Dreadnought adds "Extra-Heavy Weapons": the Conversion Beamer Las-Cannon and Fusion Gun. These are deadlier than the normal heavy weapons, but they don't get Order or Equipment card bonuses. The Aliens get 10 points for each extra-heavy weapon Marine killed.

Conversion Beamer:

Conversion Beamer

The conversion beamer has to be fired at a wall or a closed door. I does not require line of sight to the wall or door.  The damage can affect the firer if he is close enough, making it difficult to get into position. You roll 3 red dice, the example show what happens if your total is 6.

A Psilencer, but I pretend it is a Conversion Beamer

Las-Cannon:

The Las-Cannon has 3 red dice, you can make 3 attacks with 1 die each, 1 attack with 3, or 2 attacks, 1 with 2 and the other with 1. Each attach affects a 2x2 square. Below, the marine rolls 2 dice against the aliens on the left, and 1 die against the aliens above. You don't seem to need line of sight on the far corner.

Las-Cannon

Fusion Gun:

There is also the Fusion Gun, which is a Plasma Gun that rolls 3 red dice, but you roll separately for each target. Not very imaginative.

Tarantula:

There is also the Tarantula, which is a miniature operated by a separate marine. It can't move and fire in the same turn. It is a Las-Cannon that rolls 3 red dice, has a 90° firing arc, and a move of six when adjacent to a Marine Tarantula Gunner. The gunner has an armor value of 4 from the front arc, so it can fight a Dreadnought face to face, although the Alien will attack it from behind with an Orc instead.

Arc of fire

Miniatures:

You can pretend that the Plasma gun is a Conversion Beamer. Or use the EM4 Space Rangers 1=Fusion, 2=conversion, 3=Las-Cannon:

The EM 4 Mechs have a dual Las-Cannon, you could glue it to a base and call it a Tarantula. The EM4 minis are really cheap. They also have a rocket pod, so you could have a "Black Widow" which is a Tarantula that works like a rocket launcher, except with 3 red die.