Catacombs Walkthrough

You need to restore the Tattered Mousoleum Map in order to visit the Catacombs. Go to the Cartographer in the Bazaar and get your Tattered Mousoleum Map restored for 160,000 Gold. This will take 5 days. It means that for for the next 5 days you will have no access to the Mousoleum. After 5 days collect your restored map from the Cartographer and head to the Catacombs if you are Legendary.

Cheese:
1) Radioactive Blue Cheese
Collect as many RB potions as you can in the Lab. You will need a continuous supply of Radioactive Blue cheese in the Catacombs. 
When RB cheese goes stale it becomes Radioactive Sludge. This is automatically put into your crafting inventory.

2) Ancient Cheese
Crafting recipe: (6) Ionized Salt + (3) Stale Cheese = (3) Ancient Cheese
Crafting recipe: (3) Magic Essence + (6) Ionized Salt + (3) Stale Cheese = (6) Ancient Cheese
Stale cheese is obtained when Brie, Swiss, Marble, Cheddar or White Cheddar goes stale on your trap. It is automatically put into your crafting inventory.
Ancient cheese has a better attraction rate than RB.

Arcane Traps:
1) Obelisk of Slumber (OoS)
Buy the Obelisk of Slumber trap in the Catacombs General Store for $316,350. Alternatively use the Bottomless Grave or Sinister/Ambrosial traps until you can afford the Obelisk of Slumber. These shadow traps are not advisable for the long term in the Catacombs.

2) Obelisk of Incineration (OoI)
Crafting recipe: (1) Obelisk of Incineration Blueprints + (1) Obelisk Parts + (1) Coal+ (2) Scrap Metal + (3) Splintered Wood 
Buy the Obelisk of Incineration Blueprints from the Catacombs General Store for $45,079.
Obtain the Obelisk of Slumber parts by using the Hunters Hammer on the Obelisk of Slumber trap. (Do not smash your OoS until you have 1 piece of coal and 2 scrap metal. This may take some time.)
Coal is dropped by Keeper and Scavenger mice.
Scrap Metal is dropped by Scavenger mice.
Splintered Wood can be bought from the Training Grounds General Store.

3) Arcane Capturing Rod Of Never Yielding Mystery (ACRONYM)
Crafting recipe: (12) Scrap Metal + (1) Onyx Stone + (3) Magic Essence + (1) Obelisk Parts + (1) Mysterious Blueprints

Buy the Mysterious Blueprints at the Catacombs Trapsmith for $632,700.
Obtain the Onyx Stone from the Master of the Dojo in the Pinnacle Chamber.
Obtain Magic Essence by using the Hunter's Hammer on Super|brie+.
The ACRONYM is by far the best trap to use in the Catacombs.

Loot:
The Front cover of Plankrun's journal is dropped by Keeper mice in the Catacombs

Extracted info from Amy Wong on MouseHunt Forums@FaceBook

FAQ:

1. What am I doing in the Catacombs? 
Your objective is to catch all the new mice, make gold, collect loot, craft traps and climb the leaderboard.

2. What is the best trap to use? 
ACRONYM

3. What is the best base to use? 
Polar for a rounded effect, Explosive to create more stale cheese, Dehydration for a higher attraction rate.

4. What is the best cheese to use?
Ancient cheese or Radioactive Blue cheese.

5. Is it possible to catch Forgotten/Shadow mice using normal cheese?
Not really. The attraction rate will be very very bad.

6. Where is stale cheese sold?
 Stale cheese is obtained when the cheese on your trap goes stale. It is no longer dropped as loot.

7. How is RB sludge obtained?
 RB sludge is obtained when RB cheese goes stale on your trap. RB cheese does not become stale cheese.

8. What is the use of RB sludge?
It's use has not been discovered.

9. Where to obtain Obelisk Parts?
Use the Hunter's Hammer on your Obelisk of Slumber. This will smash your OoS and you will no longer have an OoS trap.

10. How to re-craft the OoS trap?
You will need (1)Obelisk parts + (1) Bead of Slumber. The Bead of Slumber is available from the Catacombs General Store for $2,000.

11. Where are the blueprints sold?
 Catacombs General Store. Once you use it for crafting you are unable to sell it back to the General Store. 

12. Is it necessary to return to the Cartographer to pick up the restored map?
 Yes. To check it's progress, click on Shops, then Cartographer.

13. How long does the Cartographer take to restore the map?
5 days. 

14. What do I do for 5 days?
Go to the Lab and stock up on RB potions.

15. Can I go to the Mousoleum whilst my map is being restored? Not unless you have a second Mousoleum map.

16. Is it necessary to craft the OoI?
No.

17. Craft OoI or wait until ACRONYM?
 Wait until ACRONYM if you already have the OoS.

18. Do the Ambush/ZLM/SnoB/FF/DB/DDB/SA traps work in the Catacombs?
 No. 

19. Which is better, OoS or BG?
OoS.

20. Can I use my BG/Sinister/Ambrosial till I have all the parts for the ACRONYM?
 Not a good idea.

21. What are Forgotten mice?
 Scavenger, Keeper, Golem, Spider and Ooze mice.

22. Is it a good idea to use an Arcane trap to catch Forgotten mice?
Yes.

23. Where can I catch the Forgotten mice?
 In the Catacombs.

24. Why does it say "my weapon appeared to be ineffective"?
You are using the wrong trap. 

25. Why does it say "my weapon was very effective"?
You are using the right trap.

26. How effective is very effective?
Very. Much more than ineffective.

27. No coal/scrap metal dropped for days, is this a bug?
No just bad luck. Patience is needed.

28. How to obtain scrap metal faster?
Catch more Scavenger mice.

29. Is it possible to craft the OoS from the OoI?
 Yes by smashing the OoI. However you will lose all your other parts. 

30. What to do with the extra scrap metal/coal/RB Sludge?
 Keep it in your inventory.

31. Can scrap metal/coal/RB sludge/RB/potions/blueprints/traps/Obelisk parts be sold to other hunters?
No. Why? Because the Developers of Mousehunt has not developed such a trade system.

32. Where do I find more people to join my hunting group?
 Look for various Add Me lists instead of creating multiple Add Me lists. Feel free to add me.

33. Why can't I access the Catacombs? You need to be at least Legendary AND your map needs to be fully restored by the Cartographer.

34. I have not caught anything for X hours, am I doing something wrong?
If you are using an Arcane trap and RB or Ancient cheese you are not doing anything wrong. You are just having a bad run. 

35. How do I get to the Catacombs?
You will need to get your Tattered Mousoleum Map repaired at the Bazaar Cartographer.

36. How to catch mice in the Catacombs?
By using RB or Ancient cheese and an Arcane trap.

37. Can Ancient cheese be dropped?
No you need to craft it.

38. Should I use my Corrupted RB potions?
Yes it will save you the trip to the Lab.

39. Should I buy X or wait till Ronza comes?
Ronza's visits are rare and far between. Up to you.

40. What might Ronza by selling?
I don't know. We can only speculate.

41. Lootless Scavengers?
 Not all Scavengers drop loot.

42. How do I get Scrap Metal?
 It is dropped by Scavenger mice.

43. How do I get Coal?
It is dropped by Keeper and Scavenger mice.

44. How much gold / points can I make in the Catacombs?
 Averages about 200,000+ gold /points per 120 hunts, before cheese costs. Net profit is about 2,000 gold / points per cheese.

45. Where is the Catacombs?
 It is under the Mousoleum.

46. Which cheese should be used to make Stale cheese?
Cheddar on Explosive base.

47. What is after the Catacombs?
 We do not know yet.

48. Is Plankrun's Front cover still available from the Keeper mouse?
Yes. It is rare, therefore patience is needed.

49. Do I need Plankrun's Front cover?
No.

50. I can't find the Onyx stone?
 You need to go to the Pinnacle Chamber and catch a Master of the Dojo mouse using Rumble cheese.

51. Where is Super|brie+ sold?
Click on the blue Donate button, or go to Friends, then Trade Super|brie+. SB+ can be bought in any location. 

52. Does donating increase luck?
Yes, it gives u a Golden Shield with +7 luck for one to four  month depending amount of SB+ bought.

53. What happened to the Acolyte?
 It was accidentally released and has been caught.

54. I do not have enough gold to buy X, where can I get gold? Please be patient and save your gold from catching mice. It is not recommended that you create a thread especially asking for gold. 

55. I do not have enough Super|brie+, where can I get free SB+? Download the MH toolbar and obtain 3 SB+ per day from doing searches. It is not recommended that you create a thread especially asking for SB+. 

56. Where to find more detailed information on Mousehunt? Mousehunt Wiki. Located under Lore, then MH Wiki. 
http://mhwiki.hitgrab.com/wiki/