I'm trying to figure out exactly what it did. It looks like maybe as it tried to "land" from that pitifully low and graceless hop, with its one leg flailing out to the side/back in a poor imitation of a move that looks like floating when a real ballerina does it, it landed on the outside of its foot (because its body mass was being pulled in the opposite direction due to the aforementioned flailing leg) and somehow managed to pull or tear a tendon in the back of its mushy thigh? I guess? That's what happens when you try to fling sacks of potatoes around, though: the uneven, ever-shifting weight doesn't allow for proper balance.