'Zyxt' which is an obsolete Kentish word apparently means (you) saw (ie. the 2nd singular indicative present form of the verb 'to see'). And, by golly, I tried my darndest to use it in a sentence some time today but I have failed. This is the last word in the Online version of the OED. However, a bit of combing the web turned up 'zyzzyva' which is a tropical American weevil, a heck of a lot easier to write about. It seemed as though it may have been a word created through onomatopoeia but no, a quick look at Wikipedia (that never lies ...) says that the word may have been fabricated so that it would always be positioned last in any index. It is a pretty insect indeed but, as a weevil, is born to munch and probably made its mark on the Brazilian forests where it was first discovered by an Irish entomologist, Tom Casey.
It is roughly ant sized (the reference doesn't say what size ant!). Neither does it say what it eats or if it has any known predators.
This leads me, in a convoluted way, to the actual point of this article. When you are writing, be sure to ask yourself all those lead questions that a curious person may put to you in a conversation. Don't be content to leave your descriptions as loose as 'the zyzzyva was ant-sized' but do some research in detail and then work out which facts will suit your story arc. Balzac was a master of this sort of interesting 'gossip' which, like the works of Proust, Hugo and Zola, became vital historical clues on what Paris once was like.
In the meantime, if you see a zyzzyva on your plants, try to figure out what it eats and add that to the Wikipedia listing!