14.1 Mass invasion is by far the simplest and most viscerally rewarding of all the invasion types but should only be considered when you enjoy a clear military superiority. Bring all your troops, divide them up amongst the continents, based on their defensive abilities, and get going. It’s not an exclusive strategy and generally, orbital bombardment of key military installations is undertaken just before and during the landing process. You probably want to take out any missile defenses and air units as soon as possible. Use the destruction of their capital cities as an introduction, if possible try to synchronize blowing up large numbers of important cities all at once as this tends to befuddle the enemy and scare the bajeebers out of them. I do not recommend using local satellites to coordinate the timing of the attacks. After all, you have just travelled from another galaxy light years away, you are entirely capable of sending a simple signal they cannot detect to a handful of your own vessels. Or fuck it, if you aren’t capable of that, synchronize your wrist-watches with the fleet’s captains during a fucking simple meeting. Remember, you want to create an overwhelming feeling of loss and hopelessness in the defenders. Their only concern should be running, staying alive and worrying about their loved ones. Then it’s a simple matter of mopping up, destroying their communication arrays and publicly offing their politicians. Once their world goes silent you can move on, leaving your rear guard to exterminate or enslave the remaining survivors as you see fit. Also known as shock and awe.
14.2 Orbital Bombardment. Useful when the planet you’re taking has strong ground forces. The first goal of any orbital bombardment is to take out any weapons capable of deep-space firing-solutions and aerial vehicles. After which you can pick apart ground forces, communication capabilities and civilians at your leisure.
14.3 Podding. When you do not enjoy a significantly more powerful force, there are a few options you can consider instead of invading. Covert body snatching or podding is a perfectly respectable option. If it isn’t a natural genetic option, reach out to your science advisors for the appropriate technology. Essentially you want to send a few troops into rural locations around the globe where they can gradually infiltrate the residents, kidnapping, killing and assuming their identities. It’s a slow process but very effective. Once you have strong outposts you can start reaching into smaller cities and assimilating them into the fold. Be careful to not reach too high too fast. Very often a naive fifth columnist will get cocky and attempt to take a president or congressman but that is unnecessary and dangerous. Slow and steady podding wins the day.
14.4 Coming in peace with secret, nefarious purposes may be a bit of a cliché but still a highly effective way of establishing a beach-head. You will be surprised how gullible and trusting some species can be. Coming in peace allows you to infiltrate and corrupt their politics, clergy and media houses, buying time while you go about feasting on them and readying yourself for the overt action which is the next stage. In some cases the ruse has lasted for centuries but I lack the patience for the long game. It’s important to not look too terrifying to the locals, offer up petty technologies and cures to common ailments. Smile, kiss babies and try to avoid eating people who will be missed in the beginning.
14.5 Beat into submission. There will be times when the goal of an invasion is not the annihilation and dominance of the race but instead a desire to have them join your empire. Obviously the best way to show them the benefits of signing up is to beat them into submission, then, when they are defeated, sitting down and magnanimously inviting them to join in your glorious cause. If they agree, let them have the planet to themselves. I always like to keep a few officials around. That way, when they turn against you, your representatives will be killed and you will know it’s time to reinvade.
14.6 Giant reptiles. Imagine this scenario. Picture a large bustling city… oh I don’t know… let’s say, Tokyo, for example, and imagine the millions of people bustling around, going about their circadian rhythms, when a giant shadow falls across large swathes of the city. People look up in horror, scream and start running in terror. Imagine a giant, bipedal reptile, coated in a viscous fluid, roaring so loud it shatters windows all across downtown, showering civilians and cars in shards of toughened 5mm plate glass. Now it starts to walk, this abomination, each step being measured by a seismograph a few miles out of town. This reptile rears up, smashing high-rise buildings and sending debris falling, trampling cars and tanks underfoot, unware of their existence. Slow natives disappear beneath its massive claws with naught but the slightest squishing sounds emanating down the street. Now imagine, amidst all the sirens and gun fire and screaming, a small light on the horizon, slowly descending from the heavens off in the distant. Did you notice it? Would anyone? Nope. Nobody would. Now imagine that the light was, in fact, a vessel crammed with your crack troops landing at a predesignated coordinate. Giant marsupials, or anything similar, such as monsters, robots, flailing tentacle-beasts, all work just as well. The goal here is simply misdirection and it’s a highly effective and fun invasion method. If you’re wondering where you would get giant reptiles for such a purpose, you could simply take regular ones and rear them in a high oxygen and steroid environment, with some minor genetic modifications, or simply place them on an island and expose them to radiation. If your scientists can’t do that, there’s a lovely little moon on the seventh planet in the inner-most solar system of the Grixxon galaxy, that produces lizards and marsupials perfect for this purpose. Simply build the required space vessel and pick a few up at your leisure. Don’t be greedy, leave enough for the next generation of warmongers.
14.7 Gloops, slimes, blobs and Nanotech are equally fun and effective if giant lizards are a bit too garish for your tastes. Any half decent scientist should be able to produce a good gloop in a matter of months. Insist that the gloop produced is immune to fire and projectile damage and preferably capable of devouring the flesh of the inhabitants without damaging the structures they inhabit. Just ensure you can control the slime when it’s done its job. There have been occurrences where the gloop infested the entire planet making it inhospitable to the invaders themselves. It should always be vulnerable to one substance, frequency, or weapon you can use to kill it when its mission is at an end.
14.8 Psychic Takeover. If your species has a small population and some measure of psychic ability, this might be an option to you. The game play is the same as podding only you will be controlling inhabitants via psychic means instead of wearing their skins.
14.9 Farming. If you take out missile and air defenses of the planet, the game is already won. Generally it’s a good idea to cut communication and eliminate the larger standing armies, just so the locals get the message but after that, feel free to kick back. There’s no need to hurry, why not take what you need in the quantities you like and allow the planet to replenish itself. This way you can live off the planet while readying yourself for the next invasion. If there are minerals you want to mine, by all means wipe that continent clean of insurgents and their families. Otherwise, leave them alone and harvest them only when necessary; keep the planet in balance and your belly full.
14.10 Ruling the Masses. A Lazy option for invaders who want the resources of the planet but lack the manpower or the work ethic to do the digging themselves. Have your ships appear above their cities and then appear before their leader. During that meeting, express your desire for the resource using and give them a few days to prepare it and place it at a location of your choosing. If they fail to provide the meat, liquid or mineral as requested, kill a few million and then politely ask again. They will soon realize you aren’t to be trifled with. Once they start providing, you can gradually increase the amount. It helps if you have a spaceship in geosynchronous orbit above you to issue instructions, perform miraculous eclipses on command or to set assassins on fire.
14.11 Kill ’em all. Sometimes it just isn’t worth the effort. Sometimes you don’t have the resources or soldiers to engage the enemy on the ground. Sometimes they taste like rubber and the only vegetation available is all lettuce and mushroom. Sometimes it just makes better sense to set fire to the outer surface of the planet and then leave it to cool down. Some people just like to watch a planet burn.
Below is a decision tree to help you pick the invasion strategy that is best suited to your situation:
Figure 14. Decision Tree - Invasion types.