Okay, so the third thing you have to attract the flying robot on the water level.
You still have the rusty crowbar (now broken) from level 12.
Throw it next to the water, then pour awesomesauce (I'm not gonna post the walkthrough on how to get it) all over it. The robot will come closer. Push it into the water, then use it as a boat over the poisonous water area.
Now, the level 41 shark will come. If you survive 5 minutes, the octopus will come. Just try and get them to both attack you at the same time, then use your Quick-Jet move you unlocked in level 10 to jet out of the way. They will now destroy each other.
Hope this helped :)
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http://genericwalkthroughguide.com