Writing alien foods is an exercise in mild horror or body horror writing as well as shock creation. In fact, the best alien foods often resemble the things we'd never eat without desperate cause. Then again, also of the best are foods we've never thought of as they just plain don't exist in any form in the real world.
Writing alien foods isn't only about the actual food though, it is about how it is eaten. This is where body horror can truly come into play. Misplaced orifices usually make people do the double take but a much subtler form can be the use of different eating utensils. As you know, body horror can be used to create black humour and so different eating utensils can be used to create slapstick comedy.
The reason for this is that alien food is seen to obviously be different from what we eat and given that we eat almost anything that tastes good, morals sometimes taken into account and sometimes not, then what doesn't taste good or is unappealing in appearance is likely to be what an alien would eat. Never mind that there are opportunities to write delicious alien foods, most are written to horrify or amuse.
I guess that does present you, the writer, with an option to break the trend. Surprise us.
Red Dwarf has many good examples of body horror and slapstick comedy with regards to alien foods. There are mutating foods, wrong orifices and odd utensils like anti-matter chopsticks.
- Excretion based foods from those animals not normally accepted. Also Excretion based foods from our own or the host's bodies.
- Insect or arachnid based foods.
- Worm like creatures in place of noodles or stir fries.
- Emphasise the squishiness - crunchy is one of the most appealing food words so aim for the opposite.
- Reproductory organs based foods - no matter the creature they're from but the closer to home it gets the more horror is invoked.
- Unappealing colours and smells - tend towards greys, blacks, off-greens, yellows and off-oranges. Red, blue and green are appealing to the eye for most things but blue can be a bit disconcerting in food. RBG in food should be Red, Brown, Green but I'd also include bright oranges, purples and yellows in the mix.
- Fungal based foods - neither here nor there it is often seen as the most unappealing of foods by children. This impression generally remains for anything not a mushroom.
- Rats, mice or anything deemed to be disease infested - alien versions included. To willingly expose oneself to disease or imagined disease will elicit body horror in most.
- Brains based foods - any will do but the closer to home the more squeamish the audience will become, particularly if the brain is still in the skull (or original casing, whatever you make it out to be).
- Fetuses and larvae - the eating of any of these will bring about intense body horror in those who don't eat such things already (there are those who eat such things as cooked eggs with almost grown chicks boiled in them as a delicacy or as street food). But pretty much everyone will recoil from the eating of your own species young.
- Natural drugs such as licking toads and willingly being bitten by snakes will make many draw back in fear as well as horror.
- Tentacle based foods - unless the tentacle is recognised as one commonly eaten the idea of eating tentacles is quite off-putting.
- Cannibalism. Need I say more.
- Reversing the order of the orifices or at least misplacing them.
- Eating far, far too much.
- The alien eating us.
- Rely on the awkwardness created from using utensils not fitting your appendages.
- Cultural awkwardness of having to be adept without learning - use the class system alongside the above point and you have a tricky situation and slapstick moment blended together. Such moments can make for humour and cringe-worthy moments.
- Reverse the order and try to teach the alien to use your utensils.
- Create utensils similar too but not the same enough to those the audience will be familiar with but place them in extraordinary situations.
- Create utensils extremely different from those the audience will be familiar with.
- Use antiquated or uncouth methods of eating - straight off the knife or the equivalent of.
- Use no utensils at all and have the characters face-plant into the food.