Nurse Coldhoof is a Pegasus NPC, located outside the Ponydale Hospital. Talking to her initiates the Supplying the Hospital quest.
"This Hospital is closed until further notice"
[response : Ok]
"Thank you for understanding. You have a nice day."
[response : why?]
"Well, usually hospitals treat ponies, but no one's getting ill, injured, or hurt in any way whatsoever lately."
"It's the darnest thing..."
"I hope you understand. Just be on your way and get back to your fun!"