There are probably lots of these that I have forgotten as I watched the episodes over the course of days, even weeks.
Season 1, Episode 11 - The Box
A magic chest that, when opened, reveals a portal to another world or pocket dimension. The portal changes with the chest's location, so to access a particular world/dimension, the chest must be placed in the correct spot. Particular worlds have their own portal locations throughout the world. If the chest is not palced in a portal spot, then whatever is placed inside at that location remains in a pocket dimension until the chest is once more opened in that spot. What this means is that if you put something in the chest, then moved the chest a few feet to the side, then it would be empty when you opened it.