The goblins head to the wizard's graveyard after they help a prisoner escape and find the voodoo doll of the king.
How to Clear Gobliiins Level 13
Switch to 
Hooter/Ignatius and change the cursor to a fist, and
click the tree roots to make one of the roots move up. Then switch to
Dwayne/Oups and change the cursor to an open hand, and click
the object that was beneath the tree root to get a birdcall. Change the
cursor to a fist and click the eggs in the tree.
Wait a while, and the bird will fly away, and one of the eggs will sprout
legs and hop up and down. Switch to 
Bobo/Asgard and change the
cursor to a fist, and click the bouncing egg. Cracks will form in the eggshell,
and wings will pop out. Switch to Hooter/Ignatius and have him use
magic on the egg. The wings will get bigger, and the egg will take him to the
right side of the screen.
Have him use magic on the horn on the ground to move it out of the way.
Then switch to Dwayne/Oups and have him pick up the bottle of
elixir. Make sure Hooter/Ignatius used magic to move the
horn out of the way. Then have Dwayne/Oups stand in
front of the two stones that are close to each other in front of the stone wall,
then change the cursor to a fist and click him to use the elixir and turn
invisible. Then repeatedly click the area near the carrot on the right side
of the screen to make him
go past the wizard while invisible. Change the cursor to an open hand and have
him pick up the carrot.
Before the next step, switch to Bobo/Asgard and
have him stand in front of the two stones
that are close to each other in front of the stone wall.
Then switch back to Dwayne/Oups and
change the cursor to a fist, and click the hole
that the rat is coming out of on the right side of the screen.
Then switch to Hooter/Ignatius and have him use magic on the rat.
The wizard will be distracted by the illusion. Have Bobo/Asgard
walk to the right side of the screen while the wizard is distracted.
This completes the level. Click the flashing "Go" in the right side of the screen. Make a note of the code in the bottom-left of the screen ( ), then click anywhere to continue to the next level, The Carrot Patch.