In Which I Dote On A Strange Amphibian

Pleurodeles waltl is one strange newt:
Acanthoplus discoidalus has got
A rival for the title of most cute
And gruesome defense. Fresh news it is not
That this guy has this capability:
Victorians knew of it, but we've now
A better guess on methodology.
He swings his ribs right up and out, is how
He first reacts, then comes some poison goo
To flow into the wounds these spears create
In any creature's mouth that tries to chew
Him up! Sometimes this ends in cruelest fate:
Death to the snacker! The newt itself moves on
Unscathed; even the rib-holes heal anon.