The Stuck Fishhook Line (引っかかった釣り糸, Hikkakatta Tsuriito, lit. Stuck Fishing Line) is an event in Tomba! 2: The Evil Swine Return.
Free the stuck cork at the roof of the small building by the Waterfall of the Heavens.
To activate the event, you either need to talk to the fisherman on one of the platforms at the Waterfall of the Heavens, or leap on the cork which is stuck at the roof.