Form Science

To change forms, Locust must have a specific amount of energy to do so. At any form, Locust is able to switch back to Form 0, his true form, at any time if he has enough energy. Once he reaches form 4 however, he is able to switch to any form before F4 with the amount of stored energy he already has. Locust is able to switch into Elder Locust once he reaches form 4 or form 5 (not confirmed canon), although it takes a lot more energy to switch to Elder Locust from F4. Locust can gain energy by absorbing the energy of his victims or opponents. His forms are actually influenced somewhat by what he consumes or absorbs energy from in the form before. F1 suggests that F0 had killed or absorbed energy from another Locust/Mantis Kaiju before Katydid. F2 suggests that he had absorbed energy from something resembling an Arthropod as F1, which could actually give more of the lore, as in the Trailer for Ch. 1 Remake, we see F1 battle and kill a red arthropod monster with an unconfirmed name, but we never see it in the film. This is not confirmed however, but it is very possible to be the reason F2 is an Arthropod. F3 suggests that he had either absorbed energy from something resembling a flying insect as F2, or he had actually even drained energy from Lewis between Ch 1 & 2, as well as an insect monster, explaining the reptilian-like appearance. F4 suggests that he had actually taken all, or most, of the energy from the corpses of Carlos & Lewis.