When using a Survivor, look for a Frog Statuette and use your Special Move. Click on the Frog Statuette to turn into a frog. The frog will be invisible. Use all its stamina and right click to change back to a human. You will have full stamina instead of no stamina. However, you will also have the speed of the frog and its slow stamina consumption too. To disable this, change into any animal without using your Special Move. Then, change back to human. Note: Your stamina will fall to zero again.