The Frog Suit is a Power-Up that is extremely useful in one specific type of environment, but is effectively a Poison Mushroom outside of it. One of the more common types is a power-up that grants enhanced mobility (and in some cases Super Not-Drowning Skills) in water but reduced mobility on land. In order to qualify as a Frog Suit, a power-up must be "on" continuously, as opposed to an item that is used with a button combination or other input. This is because it is inherent to the concept of the Frog Suit that the user is incurring a cost in exchange for this situational utility, and so an item that is not always on but can simply be used for a moment when the owner decides does not have such a cost.
- The Trope Namer and most iconic example is the Frog Suit from Super Mario Bros. 3. While underwater the Frog Suit allows faster swimming with far more precise control, on land the Frog Suit requires Mario to move with an awkward hopping gait.
- The Mini Mushroom from New Super Mario Bros. shrinks Mario, allowing him to enter narrow pipes and walk on water, but as it also makes Mario a One-Hit-Point Wonder it's dangerous with little to no upside outside of those situations.
- Kine from Kirby's Dreamland 2 and 3 works similarly to Mario's Frog Suit. While Kine is quite agile underwater and is essential for accessing certain areas due to his ability to swim against the current and allow Kirby to inhale underwater, on land he is very slow and makes Kirby unable to fly.
- Most of Wario's transformations in the Wario Land series are effectively Frog Suits. They're useful for doing one specific thing but otherwise hamper Wario's movement. They generally also can't be turned off at will at any moment, but must be allowed to time out or expire in some specific way.
- Pin Head in Dynamite Headdy shrinks Headdy, decreasing his movement speed and the range of his head-firing attack. It is required to enter many small passages, and it is also surprisingly useful in the final boss fight. Unlike most other heads, it cannot be canceled at will, nor does it time out; once it has been acquired, the only way to get rid of it is to collect a different head or to reach the end of the stage.
- Most transformations in Banjo-Kazooie are Frog Suits. They are required to access certain areas of the level but severely limit Banjo and Kazooie's abilities in most other respects, and as they can only be turned on and off at a specific place (or, in the case of turning them off, by going too far outside the level), using them effectively often requires keeping them through a significant chunk of territory where they aren't useful.
- The Frog Robot Armor in Megaman X 3. Similar to Mario's Frog suit, it's incredibly awkward to pilot on land compared to the other robot armors, but is the only one capable of being used in underwater areas.
- The Eyeclops helmet in Kid Chameleon. It's special attack is pretty boring compared to other helmets, but it does have the ability to make invisible platforms visible for a short time.
- The radiation shielding suit from Fallout 3 and Fallout: New Vegas. It is very useful in irradiated areas, but it's crappy armor that will get you killed in a shootout.
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