say learn, say train, or say power or something like that.
Argos will tell you to kill exactly 99 Manticores, is 6 hours!
Go down to the foot of the mountain, there are two rooms containing manticores on the way up the mountain.
My tactic was to kill these two rooms, then log out, rinse and repeat
Make sure that you dont kill too many! I recommend using a tani to get you up after 99 (otherwise you will need someone to clean in front of you to avoid killing too many)
Go back up to Argos, and again say "learn" or "power", and he will give you the shape