Spooky tree stump

I just started a new save file after the update and in Vipik city, I came across a ‘spooky tree stump’. The girl next to it said that the treats that she left were gone in the morning, so would i need to play at night the get the pokemon? Also, what is it? I’m assuming that’s it’s from the game corner deltas and this is also another question but are the deltas still available at the roggan game corner?

ok so ik its delta wooper im pretty sure u leave a rare candy and come back at midnight im like 90% about the last 2

actual midnight?