I was considering getting into this and so I did some thinking, and then some writing and then this happened.
Where a bad acorn taken root
Or was it a tree, the point is moot
Yet here we are our story began
By this unremarkable piece of land
A clever pony approached this plot
Worried by what this place would wrought
To the tree he nailed a sign
And drank from the pool, which tasted like wine
And so he left the place that day
Pulling his cart in the very same way
Unknown to him what chaos would make
Of the things he left in his wake
Around the nail ‘merged a queen anew
Within that tree her army grew and grew
Until they were finally ready to clash
As they were going to turn the land to ash
Yet chaos has a way of working things out
As from of the cart, an egg did fall out
Into this pool this egg did splash
And so it was gone quick as a flash
Sometime later the queen and her crew
Left to hunt for victims new
During this time the egg did hatch
The creature was gone before the changelings could catch
It was a phoenix dark as night
But it was still a sorry sight
Warmth it could not find in the sun or moon
Nor in fires that would bloom
And so it flew on wings of starlight
Searching for something to make things right
After much time has passed
She came upon some ponies at last
Undetectable she crept upon
So they had no idea what was going on
And yet they had no need to fear
Because what she found brought her cheer
Warmth came to her fast
Basking in the feelings of ponies past
Their passions warmed her chilly heart
Even their fears caused her to start
She stayed with them for a day and a night
Always undetectable, out of sight
Shortly after some changelings attacked
And left her party out of whack
Once day has passed she felt some pain
As she realized warmth she could not gain
Her party was but empty husks
And so she began her hunt at dusk
Undetectable was she, invisible to sight
And swiftly she flew to chase the blight
Once they were found and rent asunder
She quickly worked to loot her plunder
Much warmth she found, but it faded fast
So she found her party where it would last
She gave them her warmth and watched them renew
Until they were almost the very same crew
Exhausted was she from such an act
And so she hid in a pack to nap
Within that day they reached a city
Yet for all the stone it was rather pretty
Up she flew searching for a tower
For which to claim her bower
She found a pony, crazy he be
With a long white beard down to his knee
It turns out he could see her, try as she might
To hide from his blind eyesight
Fun they had for however a brief time
Until it became time for that pony to die
Nasty it was, a thing of chills
A murderer who wanted to pay his bills
A theft it was, “gone wrong” they said
Yet it didn’t matter because the poor pony was dead
Greif she felt, and anger that too
She plummeted through the tower, her hunt began anew
Walls could not hide him from her talons she knew
Within her heart, a fell darkness grew
She found him quickly and delighted in his fear
As he knew she would rip him ear from ear
And yet something she found that made her pause
And lose faith in her only cause
A foal there was, asleep in a crib, unaware of her presence therein
Should this creature suffer for the poor pony’s sin?
Gone was the phoenix from the home that night
And yet outside there was a terrible fight
Bones mend when they break
But a life one does not idly take
She found her calling there at last
Stopping monsters of the past
So that there will be warmth you see
For ponies like you and me
Let this serve as a cautionary tale
If against justice you do rail
As comfort you can never take
If evil follows in your wake