Pokémon Mystery Dungeon: Explorers of Time Tips

Monster Houses
If you have trouble in Monster Houses, just bring a few Petrify Orbs or Spurn Orbs. The pokemon will be petrified (unable to do anything) until you attack them. Luckily, nobody in your team will attack a petrified pokemon.

Beware of some weather (like Hail), current status effects (like Poison), and other pokemon just walking into the Monster House (like Loudred with Uproar). All can unpetrify the pokemon.