What is happening:
The pony (Polly) I need to speak to in order to advance the quest 'Slippery Slope' is missing, though the quest marker is intact.
What should be happening:
The quest pony should be standing here, ready to talk to.
Steps to reproduce the issue:
Launching the game, receiving the Slippery Slope quest, speaking with Enki and following the quest marker to locate Polly to ask about the sunflower seeds. At that point, this happens.