The green-blooded skinks of the genus Prasinohaema possess highly toxic levels of biliverdin. (That's a bile pigment).
The blood of every Green Skink is saturated w/the stuff.
And any creature who crawls, or flies, or swims, near the surface of our earth... w/that much biliverdin...technically should not.
These are busy guys, and in their free time they hide boats; really deep deep in the Adirondacks.
Near Oblivion.
This condition is caused by an excess buildup of the bile pigment biliverdin.
Concerning all other vertebrates; to have an accumulation of biliverdin to such an extreme degree, as to turn the blood and tissue green... well, this might be healthy.
At great peril, I have managed to capture these images of the elusive GBS.
I share them with you.
GBS makes many mountains quiver.