Wario's Different Forms
Wario's various forms throughout the series. These range from powerups to simply conditions caused by enemies. From Wario Land 2 through 4, Wario can have several status effects inflicted on him that are sometimes helpful for reaching certain areas, but are otherwise general nuisances in Wario's quest.
Wario Land
Tiny Wario
In 'Wario Land' and 'Wario Land VB', Wario would become tiny when damaged by an enemy. As Tiny Wario, he could no longer use the body slam attack or pick up and throw enemies. Finding any pot would return him to normal size or Power Up, depending on which he grabbed.
Tiny Wario reappears in 'Wario Land 2' as a transformation, caused by the spell-casting Gooms in some levels. While tiny, Wario could jump higher, and would return to normal when damaged or if he fell into water. Tiny Wario also appears with his own character level in Wario Ware: Smooth Moves when a motorcycle build by Penny Crygor turns Wario into hundreds of Tiny Warios.
Bull Wario
Dragon Wario
Jet Wario
Virtual Boy Wario Land
Sea Dragon Wario
King Dragon Wario
Wario Land 2, 3, and 4
Crazy Wario
When Wario gets hit by a ball thrown by a penguin in 'Wario Land 2', he becomes Crazy Wario. While it is hard to control Wario, he can burp at enemies to defeat them. Falling into water or being damaged will cure him. Crazy Wario also appears in 'Wario Land 3' if Wario is hit by a certain enemy, though he can no longer burp. In this case, it is a complete inconvenience...
Fat Wario
Pigging out (more than usual, anyway) on stuff like cake, doughnuts, and apples will turn Wario into Fat Wario in 'Wario Land 2-4'. As Fat Wario, Wario throws his weight around to defeat any enemy just by touching it and break through especially hard blocks. However, he is forced to plod along at a snail's pace and can barely jump at all. Constant walking or falling into water will relieve Wario of his girth.
Flat Wario
Often unavoidable, the falling weights in 'Wario Land 2-4' can squash Wario into a pancake, forcing him to waddle along the ground and shorten his jump. On the bright side, he can slip through passages he would normally have to crawl though and drift through the air, making it easier (or possible) to reach some hidden areas. Getting wet will return Wario to his normal shape, as will certain enemies and machines.
Flaming Wario (aka Hot Wario)
A somewhat uncontrollable transformation in 'Wario Land 2-4', Flaming Wario starts with his pants caught on fire, in which he runs back and forth across an area and can only jump. The flames eventually spread across Wario's entire body, so that he can no longer jump but can control where he's going. While on fire, Wario can light torches and destroy certain blocks. Jumping into water can cure Wario, or just waiting until he burns himself out.
Puffy Wario
Presumably proof of Wario's allergy to bee stings, Wario's face swells like a balloon when he is stung or shot by certain arrows. As Puffy Wario, Wario will float upwards uncontrollably, though able to control his horizontal movement, and only running into spikes or the ceiling will turn him back to normal. In Wario World, the Winter Windster will puff Wario up when it possesses him, though he looks more like Balloon Mario...
Zombie Wario
Wario's most grotesque transformation, Zombie Wario is the result of being touched by a ghost, bitten by a zombie, or spit at by a skeleton in 'Wario Land 2-4'. As a zombie, Wario is impervious to damage, can defeat enemies by touch, and can fall through thin floors. However, he also moves slowly and can barely jump. To return to normal, Zombie Wario can fall into water or walk into a patch of light. In Wario Land 4, certain enemies can only be damaged if Wario is a zombie.