And look what I found when I was perusing my anthology of Irish poetry:

Leaf-eater
Thomas Kinsella

On a shrub in the heart of the garden,
On an outer leaf, a grub twists
Half its body, a tendril,
This way and that in blind
Space: no leaf or twig
Anywhere in reach; then gropes
Back on itself and begins
To eat its own leaf.

from Contemporary Irish Poetry ed. Paul Muldoon

And for me, I would have been incapable of writing anything about it except as some kind of unutterable horror, which in some sense, is what this poem seems to be about. Though, given its political bent, it is not so much unspeakable as nameless, and not so much horror as anxiety and frustration for the Irish condition.