Wash live crabs. Cut each crab into two, crosswise. Save the crab fat.
Pare guavas and slice each guava in half.
Scoop out the seeds and set aside the guava meat.
Transfer seeds to saucepan. Add 1/4 cup water and boil.
Strain guava broth to separate from seeds.
Heat saucepan with oil and saute garlic until light brown.
Add guava meat, guava broth, crab meat, crab fat and the rest of the water.
Put salt and sugar and allow to boil until crabs are cooked around 20 minutes.
Serve hot. Serves 8.