In the Book of Giants, it is told that the angels not only mated with the women of Earth, but also with 200 of every animal species.1 Logic then tells me that, just as the spirits of the giants, after their death, became evil spirits on earth, these angel-animal monsters' spirits, became evil spirits on earth (after their death).
Now, this is a key to understand much of the ancient lore and myths. Why is it that so many people through the years, have seen strange and mystical animals, but never managed to capture them or come up with any physical proof of their existence? Well, they may have been these angel-animals', or anganimals, as I call them, spirits. Like the Loch Ness Monster, or any of the many similar lake monsters that are told about in numerous ancient accounts. They have to be here, if we believe what the holy scriptures tell us. These monsters are also hinted at in the Bible, as the ariels, and satyrs.2 The Book of Giants just gives us a bit more of the background (along with Enoch).
Hittite image of bull-men and lion-men from The Herald's Wall relief, Carchemish.
With this in mind, just think of any of those mystical and mythical creatures that come to memory, like mermen and mermaids, minotaurs, centaurs, dogmen, goatmen, batmen?, lizardmen, dragons, speaking animals, and so on. They may all have been angimals, either in the flesh, or their left over spirits.
A common misunderstanding of those creatures among "nephilim researchers", is that they were cross breedings between humans and animals, and therefore some ancient variant, or beginning, of transhumanism. Well, there may have been such creatures too, but the old myths all agree that these creatures were produced by the gods*, agreeing therefore with what the Book of Giants said, and giving us the clue why their spirits, or ghosts, still may be around. Because, just as the evil spirits of the nephilim still are around, the angimal spirits have to be around, too - because their fathers were angels.
* Thus, what happened, at least mostly, (in the ancient world) was not transhumanism, but transangeloism.
1 "They begot giants and monsters":
The two hundred angels choose animals, including presumably humans, on which to perform unnatural acts.
1Q23 Frags. 1 + 6 +22 1[. . . two hundred] 2donkeys, two hundred asses, two hundr[ed . . . rams of the] 3flock, two hundred goats, two hundred [. . . beasts of the] 4field from every animal, and thousands from every [bird . . .] 5[. . .] then [. . .]
The outcome of the demonic corruption was violence, perversion, and a brood of monstrous beings (cf Gen. 6:4, and the Book of Watchers from 1 Enoch, text 36).
4Q531 Frag. 1 1[. . .] they defiled [. . .] 2[. . . they begot] giants and monsters [. . .] 3[. . .] they begot and, behold, a[ll the earth was corrupted . . .]
From "The Dead Sea Scrolls, A New Translation", M. Wise, p . 291.
2 Lion-men, and goat-men; 2 Sam. 23:20, Isa. 13:21, Isa. 34:14.