actually, a normal face hugger can infect a a kaiju, the bigger the creature, the easier it is for the face hugger to impregnate them. they can crawl into the mouth, and down the throat and manually release the embryo which will then begin to grow as it normally would for a human. the chestburster would probably be the size of a small building, it'd be just big enough to cause a fatal wound on their host, and can you imagine what the resulting creature would be like? something similar to the picture i imagine; larger then the already gigantic kaiju, and faster and stronger too. and then there's all the acid blood... i love your work on this my good sir