You have to jump from where the Princess is, either to the left or right. Then wait until the robot shoots with his laser (he has to be right below it when it falls).
The lower gravity there lets you jump farther : you can jump from the robot suit to the pedestal, and to either hanging chandelier.
First you have to bomb Mordred two times in the orb with the bombs, then you have to get hit one time when Merlin gets zapped. Then, jump onto the robots middle part of the machine and jump up the ledge to the princess. Last, you jump over to the chandelier.
Once Merlin is zapped, JUMP to avoid being zapped. Duck down until the robot comes right above you. Jump up onto it, between the arms, and then over to the pedestal where the Princess is. Jump from there to one of the hanging chandeliers. Mordred will roll beneath you and shoot at you. When he does, he'll hit the chandelier and it will crash onto him. Repeat this for the chandelier on the other side of the room. (That is the end!)
In the final battle against Mordred in his robot warrior suit, you have to drop the ceiling candle holders on him. Duck down until he comes over you, then jump up on the robot and to the central pedestal where the Princess is. From there, jump left or right onto a chandelier and Mordred will roll under it and shoot at you. When he does, it will crash down on him. Repeat this on the opposite side of the room and you win.
It is visible as a small sparkle or flash of light halfway up the fountain. It only appears when you jump onto it.
Chandeliers are light fixtures dangling from the ceiling. There are two large ceiling fixtures that hold candles in Mordred's castle, one on each side of the platform. To reach them, climb onto the robot and jump to the platform, then to a fixture. Dodge any laser shots. When you jump onto one, he shoots at it and brings it crashing down on himself. You have to get him to shoot both of them.
On Astro Knights Island, you wait for a platform to come down to a level so that you can jump onto it. However, the 6th platform never gets lower than the 5th, so you should jump when both platforms are moving rapidly down. The 6th platform should fall right under you.
As Merlin the owl, dodge the projectiles and swoop down to the bombs, avoiding the spinning blades, and drop the bomb on the robot when it blinks red. As your player, duck down until the robot is directly over you, then jump onto the robot, then the pedestal, then the chandelier.
The list given to you by the Queen shows it at X-83 Y-20, up and right from the planet Poptropica. To land, click on the planet.
The captive invader robot : You will have to enter the dungeon twice, once from the castle library and once from the underground tunnel (Mordred's laboratory).(see the related questions)Mordred's robot warrior: As Merlin the owl, dodge the projectiles and swoop down to the bombs, avoiding the spinning blades, and drop the bomb on the robot when it blinks red. As your player, duck down until the robot is directly over you, then jump onto the robot, then the pedestal, then the chandelier. Mordred will then shoot a laser causing the chandelier to break and hit him. Repeat this with other chandelier. (there are two chandeliers)(see the related question)
There are no plants to click on. You click on the lower shelf in the castle library (McM) and click the "planets" when you arrive at them. On the Jungle Planet, the elevator plants work automatically when you jump onto them.
You shoot the space sharks, and run away slowly. They follow you, so if you get them near the black hole, they get sucked in. (Black Hole is up and left, at X-85 Y-47.)
After Merlin gets zapped, Mordred shoots at you. Jump out of the way, then crouch down *wherever* you are, because the robot suit will roll right on top of you. You can safely climb up between the sword arms, then jump to the pedestal where the Princess is. From there, jump to one of the light fixtures (chandeliers) and Mordred will roll under you and shoot. This will bring the chandelier down on him. Move to one side and crouch down again, because you have to climb the robot again, and jump to the chandelier on the other side. When he shoots this one, it falls onto him and destroys the robot suit. The Princess will knock out Mordred and you have won the Island Medallion. (You receive your knighthood in Arturus.)