Okay, crazy fanfic time.
The Mane 6 are having a picnic near Discord’s statue (this is pre-reformation). A rumble from a far-off Ursa Major causes a tremor that knocks over the statue, breaking it into pieces. This frees Discord, but once he finds out he’s now in pieces, he decides to subject the Mane 6 to the same fate, the difference being that Discord can easily reassemble himself at will.
So now their legs, torsos, horns and wings are scattered all over Ponyville, and the heads of the Mane 6 must roll (or something) all over town and rebuild themselves. Things get awkward when they find out that, even when/if they do manage to put themselves back together, they can be taken right off again, even things that didn’t come off the first time, like eyes and ears.