In the example above you see a ghost (temporary Boo graphic) being spawned and activating after the player moves (that's how it gets evaluated). It also has a function that checks to see if the player occupies the same spot on the grid as the entity and activates the appropriate action. In the video above it simply updates the dialogue box with some debug text.
In other news, I'm thinking about the title Hondenkat: The Stars From Which They Came. Hond en kat is Dutch for "dog and cat". The main avatars in the game will be dogs and cats to begin with, so it's appropriate.
And also, happy one month birthday of development!