Fishin' Boo Riding
Fishing Boo is an enemy in SMW which is a boo in a Lakitu cloud holding a fishing rod with a harmful fire on the end of it. The Fishing Boo follows Mario while moving up and down and left and right in a slightly elliptical pattern. A Kaizo level may require you to spin jump on the fishing boo to cross large areas, navigate on the ground or in water avoid his fire, or combinations of both. A very important note is that Fishin Boo's fire can flick left or right when he turns around, moving very quickly in the opposite direction which can be difficult to avoid.
When spin jumping on the fishing boo, if you get the boo up to full speed going right or left, you can also hold the same direction with mario and fishing boo will match his speed.
The player will manipulate the fishing boo in much the same way they would a disco shell, swinging the boo in opposite directions in order to either get a more favorable initial jump off him or to manipulate a wider opening to pass by his fire. The most important thing to remember when attempting to manipulate the Fishin Boo while dodging his fire is to get him moving in an ellipsis. You can tell when he is because is fire will move in a horizontal oval as opposed to being closer to a diagonal line, which is an unfavorable pattern because the fire is more unpredicatable and spend more time closer to Mario's vicinity. If the Fishin Boo has a bad pattern it can be helpful to attempt to swing him out wider left and right to reset him into a better pattern.
Ultimately, getting good at riding and dodging the Fishin Boo will take practice.