Go to Yulgar's shop when Hans is there. Ask "What happened to Yulgar?" Hans will say a 
lot of things. Click "What happened?" then Twig will come out. Go with Twig. You will go 
to Twig's dream place. Your head will disappear. You will fight a whole group of Piranhas.
Once you defeat them, you will fight an ice cream dish. Once you defeat him you will go 
back to Twig and return to Hans' shop after that. Once you have returned to town go to 
Warlic's shop. Do the potion "Moglin Essence + Frogzard Tear + Bad Juice and you will 
then have a Fish Head.