Nothing. All you do is carry it in your toolbox and go to the 36th-98th floor f Burid Relic to attract Mew.
to draw mew to you at buried relic
at the buried relic f50-f99 with music box in your tool box
you go to the buried relic and it atrracts mew
it is just the last floor if you how the music box that is the last floor to freind mew
it makes mew appear past floor 50 of the buried relic
It appears randomly (on any floor) and you must have the music box that you get from defeating the 3 Regis.
well first you got to get the music box and go to floors 15-99 to fin him sleeping
my friend told me that if you have the music box in your toolbox- and if you have the final island friend area- mew will appear in a monster house without you using the box. only on about floor 75+
Complete the Buried Relic. Then go back to the Buried Relic with the Music Box. Mew will appear somewhere in the dungeon when this happens, so look all over for him!
you can find him in floor 33 and up and holding the music box in the bag --actually you find him through the floors 36-98 and the leader must have the music box, good luck!
go to buried relic and make sure u have a friend bow and a music box in your bag.
the answer would be mew but mew is not at the end you have to have music box and luck to see him.