As he struck the ground the four loonies giggled. Their great, idiotic heads, looking like nothing so much as the comic faces painted on Sunday balloons for children, swayed in unison on their five-foot necks, as thin as Grant's wrist.
"Get out!" he blazed, scrambling erect. "Beat it, skiddoo, scram! No chocolate. No candy. Not until you learn that I want ferva leaves, and not any junk you happen to grab. Clear out!"
The loonies—Lunae Jovis Magnicapites, or literally, Bigheads of Jupiter's Moon—backed away, giggling plaintively. Beyond doubt, they considered Grant fully as idiotic as he considered them, and were quite unable to understand the reasons for his anger. But they certainly realized that no candy was to be forthcoming, and their giggles took on a note of keen disappointment.
So keen, indeed, that the leader, after twisting his ridiculous blue face in an imbecilic grin at Grant, voiced a last wild giggle and dashed his head against a glittering stone-bark tree. His companions casually picked up his body and moved off, with his head dragging behind them on its neck like a prisoner's ball on a chain.
And this was originally a Victorian version of a prehistoric animal with someone riding it - I've edited out the rear legs and the rider, and used the rider's arms as its hands - does it seem to fit the description? I know the neck's a bit thick, but I think in other respects it works pretty well, so much so I'm inclined to use it as it is rather than trying to change the neck.