After sailing to Scaraba, you go south and solve the sphinx's riddle to open the pyramid.
Explore the Pyramid
In the pyramid, go east from the entrance. Open the casket on the way to get a Viper. Keep going east until you reach a room with a sarcophagus in the middle. Go through the upper-left door in that room if you want a Bag of Dragonite.
Then go back to the sarcophagus room and go through the door on the right. Keep going east and open the caskets on the way to get a Speed Capsule and a Cup of Lifenoodles.
Continue going east and you will find a casket blocking a door. Check on it to start the boss battle.
The Guardian General has 831 HP. Use Freeze and Big Bottle Rockets and Bombs, and have Paula and Poo use PSI Magnet to drain the 6 PP that the Guardian General has. Use Ness's Shields to protect against the physical attacks that the Guardian General uses.
Move the Sarcophagus
Go through the door that the Guardian General was blocking. Open the casket in this room to get a Rain Pendant. Then step on the floor switch.
Go west to return to the room with the sarcophagus. It has moved, revealing a hole. Fall down the hole, then check on the object on the platform to get the Hawk Eye. Give the Hawk Eye to Poo.
Go east. When you find a casket, open it to get a Diamond Band. Then fall down the hole. Go east from there to leave the pyramid.
Part with Poo
Poo will soon leave for a while, so remove anything that he is carrying that you might want.
Go south and the Star Master will take Poo with him.