To do this you have to go to the ankous, level 75 monsters found in level 4 in the stronghold of security, near the ladder you used to get down to the fourth level.
Now to make your random event come you have to fight the ankous, a 60+ combat level will be useful you should also take a full inventory of lobsters. Once you have fought at least one ankou you must stay in that area for 13 minutes. After that, pick up some bones from the floor or if there isn't any there kill an ankou and pick up the bones it drops and bury them. When this is done you should get a random event if you don't get a random event then just wait about a minute and try again. Remember that the ankous will attack you if you haven't been there for about six minutes. This process can be repeated over and over again just wait 13 minutes after your last random event and bury some bones again.
The events you get here are usually ones you already have done before this means that you will rarely get a costume event like mime or gravedigger if you haven't already got all the items from the event, mask, top, bottoms.
