The Thieving Room is a type of Puzzle Room found in the Chambers of Xeric. The room is focused on making use of the Thieving skill, by looting chests found around the room in search of cavern grubs. These grubs are then deposited into a Trough at the front of the room, where a Corrupted Scavenger will eat them. Once he has been fed enough of the Cavern Grubs, he will stop blocking the exit and players will be able to progress to the next room..
How to complete the Thieving Room in CoX?
- Enter the room and use the chest to deposit all of your items in private.
- With an empty inventory begin collecting as Cavern Grubs
- When you get around 10 grubs, deposit them to let the Corrupted Scavenger start eating
- Continuing collecting and depositing them in the trough until his hp bar is fully green and he unblocks the exit.
- Remember to grab your gear once more from private and continue on with the raid.
Number of Grubs per Chest
The number of grubs found in each chest varies. Players with a higher thieving level have access to more grubs and more often. For example a player with 95+ thieving will receive 0 grubs 50% of the time, will receive 2 grubs 40% of the time and receive 3 grubs 10% of the time. At levels 95+ there is a 0% chance of receiving 1 grub. This can be shown in the graph below.

Additionally, at level 100+ players get the chance to receive 4 cavern grubs. This is currently possible by bringing Squirk Juice or a thieving cape boost into the raid.
Number of Grubs required to complete the room
The number of grubs required to complete the room in different team sizes is always the same when using a specific formula. The formula is, 16x – 1, where x is equal to team size. The only exception to this rule is Solo’s where the amount is always 30. So the grubs required for popular scales are as follows:
- Solo – 30
- Duo – 31
- Trio – 47
- Four man – 63
- Five man – 79
However, if you feed more than the minimum threshold to clear the room. Then it will speed up the eating process making the room faster. So, it is always worthwhile to feed slightly above these thresholds. For example, 3 man teams should aim for around 55-60 grubs if playing efficiently.