Grossest SF/F scene?

Geoffrey and I were debating which scene in written SF/F is the most disturbing. So many contenders came to mind:

• Consider Phlebas: the cannibal cult leader devours a living person using specialized metal dentures
• Holdfast Chronicles: women reproducing with horses
• Perdido Street Station: human copulation with scarab-headed women
• All My Darling Daughters: sadistic schoolboys obsessed with screaming weasel sex toys
• The Sparrow: rape of Jesuit by hyperintelligent carnivorous kangaroo aliens

I find the cannibals more sickening but the weasels (Geoffrey's pick) more disturbing. I'm sure that we're leaving some out. What's your nominee?