On poptropica how do you move the big rock in front of hades throne room?

you ask Hades again after you got the mirror. But first you have to go get all the items and go to where Zeus first told you to go. he says he will destroy poptropica at midnight. the girl will tell you to go ask hades again. he will say yes because you have the transporting mirror. you go to that castle and he will say you call this little pebble a rock?, and he will push it aside. now do the rest yourself!