Advanced Xenoforms.

Aliens operate either as individual creatures or in swarms of 1D6 figures. Generally a swarm should consist of Aliens all of one type. The Queen is always a specific figure, but may be accompanied by a "Royal Guard" of 1D6-1 Elite Adult/Warriors. There can only be one Queen in each nest.

It might make an interesting scenario to play out a Hive War between two rival Queens and their children. If humans (or other species) are also involved, the Aliens will attack their rivals before the prey.

Activating Aliens
Aliens are either Active; moving around hunting for prey, or
Dormant; laired up asleep or waiting for prey to come to them.
Generally Aliens will start the game Dormant.
Dormant Aliens will become Active on an Activation level of Close or higher, or if prey or enemies move to within close range (4").
If there are no known enemy or prey near by (within two moves) Active Aliens will become dormant again.

Aliens use the following Activation Modifiers instead of the ones in the main rules.

Table 1a. Alien Activation Modifiers.

Alien Activation Options;

Close;
The aliens may move upto its full move towards an enemy unit, or into contact and may make a Close Assault attack.

Close Assault
When prey are killed or captured by Aliens, they will be taken back to the nest for use as food or as a host. Aliens with Captives move at half speed, live prey are stunned or incapacitated until they can be "gunked-up" in the nest.

Advance;
The aliens may move up to half their full move distance towards prey or an enemy position, taking advantage of cover. If the swarm has not made a Close Assault attack, they may make an Opportunity Assault in response to a prey elements move. i.e. If prey moves to within a full move of the Aliens, they may make a Close Assault attack.

Stand;
The aliens may not move towards a known enemy position, but may move into a position of cover within a half-move distance. If there is no cover within a half-move, they will lie prone facing the nearest known enemy position. If prey or enemies move to within a half move of the Aliens, they may make an Opportunity Assault attack.

Pinned;
The aliens may not move out of cover, except to fall back. If they are out in the open they will lie prone facing the nearest known enemy position. They will make best use of available cover. Pinned aliens may make an Opportunity Assault attack against prey or enemies that move to within four inches of them.

Fall-Back;
The aliens must move away from known enemy positions towards their own nest, for at least half their full move distance, or into cover which takes them away from the enemy.
The aliens may not initiate an attack, but will defend themselves in Close Assault if contacted.

Break;
The aliens abandon their position and captives and flee their full move distance towards their own base line. If they are contacted by an enemy unit, or are unable to retreat they will be destroyed.

Aliens Gaming Suggestions

* Eggs cannot move themselves, but may be moved by the Queen, Adult Aliens or curious humanoids.

Optional Rule

The first time a curious humanoid or unlucky colonist encounters an Alien Egg, They MUST go and have a closer look at it
i.e. Within springing range of the thing inside.
It is considered bad form to shoot your best buddy just because they might have a horrible Alien monster growing inside them.