4th Gen D/P/Pl strange action replay easter eggs

For me, one of the most iconic thing about Diamond/ Pearl / Platinum was the many strange mysteries that could be found with the action replay. For example: Using the action replay, go in to the church in Hearthome City and use the walk through walls cheat to run past the back wall. After a while, come back to the church and it will be titled, "foreign building". I always found that weird, especially since that church is already pretty strange. Has anyone else found any strange easter eggs while using the action replay in these games?

I always found walking through walls while watching the map and being able to tell whwre to go neat.