Roger McGough in “Unfinished Business”

Or poison you just for spite;

Won't lie in wait beneath a stone,

Until one morning out alone,

You poke a finger like a fool

Into an innocent-looking pool;

Won't grab your hand

And drag you off across the sand

Down into the bottom of the sea

To eat you dressed for Sunday tea.

The crab, I'm told, is a bundle of fun.

With claws like that? Pull the other one!