You will come across many missions in Magic Land that ask you to whack or pet a creature. Depending on the creature, it takes a different amount of whacking or petting for it to temporarily leave. You can see how many times you need to whack/pet one by hovering your mouse over the creature. E.g:
It’s a great advantage to whack and pet them when asked as they give you valuable items you will need to build a houses and businesses. (See Article 'Businesses & Houses')
If you cannot complete a mission or a house/business because you need an item from a creature but you cannot see them in your Kingdom, they will just be hiding! Take a closer look in the area, and start chopping trees down as they like to hide behind them!