Old Pony's Tale

2012
Twilight Sparkle: "Elements of Harmony, see 'Mare in the Moon'"?
Spike: But that's just an old ponies' tale.

Me: Shouldn't that be old mare's tale?
(thinking it was a joke on old wives' tale)

2015
Three years later, having re-watched that episode at least three times since then...

I was on my way to the bus stop and stopped dead in my tracks.

Old Pony's... tail. Oh.

...and then I moved on with my life, but there forever would be a hole in my heart.