Skulls are easily the hardest achievement to get, and the easiest thing to miss. They spawn very infrequently and only last for a few seconds before disappearing.

However, there is a trick to collecting them that will get you to reaching 10 skulls very easily.

To do the trick:

• Open the game, and enter your garden
  
• Scroll all the way to one side of the garden
  
• Use the button at the top to go back to the menu screen
  
• Wait for a long period of time (~1 hour or so)
  
• Go back into your garden, and scroll from one side to the other, you will likely find a skull

Skulls that spawn while you are on the menu screen appear to stay in your garden until you come back to it, at which point you then have a few seconds to find it before it's gone.

The idea is that you wait a long enough time until a skull has likely spawned, then go back into your garden and look for it. Take note that they do spawn very infrequently, so if you're checking once an hour, there is a chance one wouldn't have spawned.

The downside is your garden will not be generating any money during this time, but if it's your last achievement this is the easiest way I've found to do it.

While there is another wonderful guide that can teach you how to find out how many things you've gotten by checking ini files (I highly recommend looking it up) it does not show how many skulls or crocodiles you've clicked.

However, again there is an easy trick.

Skulls increase in value by 500 every time you claim one, meaning when you get 5000 for claiming a skull, your achievement will be completed.

Crocodiles increase in value by 200 every time you claim one, meaning when you get 6000 for claiming a crocodile, your achievement will be completed.

Good luck and happy hunting folks!