Once upon a time, in the mighty dwarven Fortress Vault Armor, the Ale of Anger there was a happy community of dwarves.
Despite being embarked adjacent to a dark pit, none of the dwarves had ever seen a goblin. Nor a cyclops. Nor Dragon. Nor any other sentient creature besides their fellow dwarves, and some Human traders that stopped by on a yearly basis to trade meat and instruments for useless trinkets and tattered clothes, presumably for their children to wear.
Indeed, such a peaceful place this fortress was, that only one dwarf had ever died. She was a miner, who had made the mistake of trying to swim through a water pipe that she herself was digging out. Not knowing exactly what to do with the deceased, they sealed her up in a rock box, and put her body in a distant forgotten corner of the fortress.
Through all these peaceful years however, the dwarves had a militia. They trained during all their waking hours, for they knew that war could come at any time. Or at least that's what the expedition leader kept telling them. So they trained with their maces and war hammers, never ceasing for a moment's rest. For the most part however, their skills were mostly wasted on walking outside, and killing snakes and harmless woodland creatures to help supplement the meat industry. This all changed one day though. They were sent out to kill a small spiny creature. It was an echidna. Hardly larger than a cat, the dwarves gave no real thought over trying to kill the small creature for burgers. The iron armored dwarves swiftly came upon the creature, giving no real thought to tactics as they began to pummel it with their silver maces. Soon the creature was dead. But... it still moved?
With a shrug, the dwarves kept hitting the spiny creature. It eventually stopped moving, and the dwarves went to leave it alone... but the dwarf with the sharpest ears heard it yet still breathed. He urged his comrades to help him finish the job. And so they kept beating on the echidna with their maces, knocking the poor creature about the wilderness surrounding the fortress. Many times the small creature was propelled away by the force of their blows, yet never taking any more real damamge than bruises on its upper body. For over Thirty days the dwarves smashed on the echidna, risking dehydration in their desperate attempt to kill that which should not be. On the Thirty First day, the Echidna did finally bleed out from its internal bleeding in the skin and muscle of its body.
And so the Squad of dwarves went home, sick from dehydration and hunger, their flasks depleted and foodstuffs long since empty, carrying back a body that would barely make more meals than they had consumed in their perilous battle to defeat the spiny creature.
There were more combat lines, but Dwarf Fortress cleaned them out to conserve memory it seems.
To make a long story short, Echidnas are sturdy little guys when it comes to pulping.