This is what you do first overload the map with trip mines you need to get on forge and tern into the oddball and click on the trip mines put everything the tallest number on summary tern back into you character. This allows you to keep throwing trip mines every second it will make it faster so you cant blow up. the map is full of squares pick one and throw the trip mines it has two fill at least one square up just keep throwing them do not touch the thumb stick just keep throwing
then things will be missing from the map and it will be a bit dark then the gardens cant see you.
Move straight a cross the gardens up the hill and you will see a big round disc thing it is big so you wont miss it just keep following the trail you will soon see the skull laying next to the big disc thing it took me a wile to find out how to do it. you will earn 25 ge but pick it up.