I had a horse I can't remember the name of who moved in, stayed three days for April Fools and then left two days later without a word. I didn't really like him so I wasn't bothered.
In Wild World, Alice moved in, I forgot to play for a day, and when I came back she was moving out. I didn't know you could stop villagers at the time, and I was sad because I barely knew her.
In New Leaf, I came back from a hiatus and found Sprinkle in my town. She pinged me to move 1-3 days later.
Ed plotted, when he was unboxing ((day 1 since he was actually in town then)) peanut plotted, peanut unboxing and ed walking around town ((day 2)), peanut now walking around town and ed pings to move ((day 3))
... I even invited Ed from the campsite. >.> Peanut was a random streetpass void I got.
I was like fine you lil ****, I took all this time to invite you and you want leave in less than a week of being here?
Fine. I don't care. Get out of my town. >.>
Rocket the gorilla(I think that's who it was) But I was tting. I talked to them once. They were gone in like a week in game. I was kinda happy that they did move since I didn't like them lol.
Five minutes. I had Flo move in, and I instantly wanted her out the moment I saw her post. I TT'd, did a favor for her, and she pinged me to leave right after I went ahead another two days.