John's Apocalypse contains some hybrid monsters. Now, the apocalyptic genre lends itself to symbolic imagery. Indeed, these are visions, so they needn't be physically realistic. Dreams and visions aren't constrained by what's physically possible. So I don't assume these are literally descriptive.
That said, I'm open to the possibility that these descriptions are physically realistic. For instance, it's the objective of transhumanists to enhance human abilities by becoming cyborgs through bioengineering. In addition, we now have genetic modification, including transgenic organisms. Then there's the specter of a head transplant:
Likewise, there was this recent experiment:
To understand how one changed into another, a team has been tampering with the molecular processes that make up a beak in chickens.
To begin to understand this, the team trawled though changes in the ways genes are expressed in the embryos of chickens and several other animals. They looked at the embryos of mice, emus, alligators, lizards and turtles, representing many of the major animal groups.
They found that birds have a unique cluster of genes related to facial development, which the non-beaked creatures lacked.
When they silenced these genes, the beak structure reverted back to its ancestral state. So too did the palatal bone in the roof of the mouth.
To make this genetic tweak, Bhullar and his colleagues isolated the proteins that would have gone on to develop beaks. Then they suppressed them using tiny beads coated with an inhibiting substance.
The team found that two proteins known to orchestrate the development of the face, FGF and Wnt, were expressed differently in bird and reptile embryos. In reptiles, the proteins were active in two small areas in the part of the embryo that turns into the face. In birds, by contrast, both proteins were expressed in a large band across the same region in the embryo. Bhullar sees the result as tentative evidence that altered FGF and Wnt activity contributed to the evolution of the beak.
To test this idea, the team added biochemicals to block the activity of both proteins in dozens of developing chicken eggs.
By tampering with genes, transferring genes, transplanting heads, &c., scientists may end up creating hybrids reminiscent of Dr. Moreau nightmarish island. The cross-species monsters in Revelation might be more realistic than we could anticipate just 50 years ago.