Click on Merlin (the mechanical owl) and the click on the "green thingy." Bingo! ;D
Green.
To power the saucer Excalibur, you need a replacement green fuel rod. There is one inside the robot invader in the dungeon. (see related question)
You get the replacement green FUEL ROD for the SAUCER Excalibur from the robot invader in the dungeon. (see related question)
For some reason, it blows itself up in the dungeon, leaving only its green fuel rod. (see related question)
The green fuel rod on the Excalibur is broken and needs replacing. There is a rod inside the robot invader in the dungeon. (see related question)
you get the green stuff an dthen put it in
The crashed saucer Excalibur needs a replacement for the broken green Fuel Rod. You can get one from the robot invader in the dungeon. (see related questions)
No, you use him to retrieve the green fuel rod from the blown-up robot. Click Merlin then click the fuel rod.
Go to the guy in the green hood. Talk to him. He will give you the manure.
The broken container of green liquid is called the "fuel rod" and powers the saucer. The only other device that might contain one if the captured robot in the dungeon.(see solution at related question)
To get the green tube in Poptropica's Astro Knights Island, you need to visit the castle courtyard and find the robot seahorse in the fountain. Ride the seahorse up to the top of the fountain to retrieve the green tube.
There is a green fuel rod insode the captured robot invader, in the castle dungeon. You can enter the rear of the cell if you threw the switch when you entered from the castle library. (see related question)