It looks like there's a double rainbow over this tray of candy. Either one of the candies is one of the keys to Elements of Harmony tree, a very tiny Rainbow Dash flew past by without them knowing it, or just random good luck is coming there way.

*Cave Plushie*
Oh boy! A tray full of candy and its all mine! Mine I tell you! All mine! Muaahahahahaha!
*Cave snatches it from him*
No, bad plushie! These aren't for you, they are for the neighborhood kids.
*Cave Plushie pouts*
Hmmmph! No fair! :'( :'( :'(
*Cave sighs*
Okay, okay! Maybe one piece of candy.
*Cave Plushie*
YA!