Ever since the 19th century, ninjas and frogs (or toads) have been synonymous with each other over in Japan, in part due to the epic 19th century poem-turned Kabuki show Jiraiya Goketsu Monogatari and the influence it had.
This ninja is almost invariably a good guy, and exhibits some kind of amazing, or even supernatural abilities, such as summoning a giant frog, turning into one themselves, or even just being a frog already. Optional is to include an arch-enemy with snake powers.
While it would seem rather outlandish for a stealth-based profession to give itself frog motifs, literary influence or not, frogs are stealthier and quicker than most give them credit for. Consider the fact that frogs can catch flies, which perceive time 4x slower than us is a testament to its speed, but also patience. Also, frogs, especially aquatic ones that frequent water, are stalking predators that are able to sneak up on their prey. Their legs give them immense jumping power that allow them to pounce on their prey and back almost instantly.
- Log Horizon: Leonardo is an Assassin-class player who dresses like a frog, emulating the hero from his favorite cartoon. This is mostly Writing Around Trademarks, but it also makes sense in the context of the trope.
- Naruto: There is an entire hidden village of frogs trained in mystical and ninja techniques. They become prominent in the series for two specific pupils:
- Jiraiya, who trained among said frogs, is able to summon a giant toad, can partially transform himself into one, and has a snake-themed enemy. Most importantly, he is an Expy of the Trope Maker himself.
- Naruto himself is tutored by Jiraiya, learning to summon frogs from the get-go and later trains under Gamabunta to learn a lot of the same jutsus that Jiraiya used.
- The Pokémon anime takes the aesthetic with Greninja in particular a step further by including a seldom-used TCG ability called Battle Bond, which—for lack of better description—combines Greninja's aura with that of its trainer. In this case, Ash. It's an ability that takes a while for them to perfect, but it helps Ash get his final badge and make it to the Final of the Lumiose Conference, going further than he'd ever gone in any prior region.
- Sgt. Frog: Lance Corporal Dororo is a frog alien who lived alongside Ninja for an extended period. Compared to his more anti-heroic (or borderline villainous) companions, he has more of a moral compass.
- Tamagotchi features Gamanosuke, a giant toad who works as the training partner of Gozarutchi the ninja.
- The anime-exclusive card "Illusion Ninjitsu Art of Hazy Toad" depicts a ninja being overshadowed by a giant golden toad. It grants a "Ninja" monster you control 1000 ATK during your opponent's Battle Phase.
- Another anime-exclusive Illegal Summon depicts the Trope Maker Jiraiya himself riding a toad. The effect allows each player to Special Summon a level 4 or lower monster from their decks, referencing Jiraiya's ability to summon a toad.
- As said above, the 19th century poem Jiraiya Goketsu Monogatari is unmistakably the Trope Maker. The titular Jiraiya (formerly Ogata Hiroyuki) was a deposed prince who learned ninjitsu and Yamabushi magic under the frog sage Senso Dojin alongside his love Tsunade, who studied Slug Magic, both to defeat the evil Snake Spirit Orochimaru and stop his plan to conquer all of Japan and eventually the world.
- Kamen Rider Zi-O: One of the Future Riders is Rentaro Kagura: Kamen Rider Shinobi, who gains his armor from a giant robot frog called Kurogane Oogama (lit. Iron Toad). In the Rider Time: Shinobi miniseries, he fights against Yaminin and his Niji no Hebi clan of Ninjas.
- Sekai Ninja Sen Jiraiya: The titular hero of the series. While he doesn't possess any magical abilities, his helmet features a frog motif and he's the descendant of a frog-like alien.
- Super Sentai:
- Ninja Sentai Kakuranger: Ninja Black is named Jiraiya and pilots frog-themed mecha, two frog-faced humanoid mechs followed by an actual frog-shaped one. For bonus points, when performing its special attacks, he stands atop the frog akin to how the literary Jiraiya is often portrayed in artworks.
- Likewise, his counterpart Adam's ninja spirit animal in Season 3 of Mighty Morphin' Power Rangers (and before that, the non-canon Mighty Morphin' Power Rangers: The Movie) is that of a frog. He also pilots the Frog Ninjazord. He's not quite happy about this initially.
- Shuriken Sentai Ninninger: The main gun sidearm of the core Ninningers, the Gama Gama Juunote is a golden gun in the shape of a frog. Its finisher is a beam in the form of its tongue. These also serves as their alarm system to warn them of active Youkai.
- In Armory & Machine, one of the enemies in the Cliffs is the Ninja Frog. They usually perform several fake-out moves before throwing a deadly powerful shuriken.
- Ensemble Stars! has Shinobu Sengoku, who styles himself on a ninja. He also has an affinity towards frogs.
- Summoning a giant fire-breathing toad is a skill of the Ninja class in Final Fantasy XIV.
- The Legend of Zelda: Breath of the Wild fully embraces the Ninja nature of the Sheikah of previous games by reinterpreting their home of Kakariko Village from a typical fantasy village into a proper feudal Japanese style village. Frog statues are frequently found all over the village, revered by the people. Their archenemies, the Yiga Clan, who serve Ganon, also have frog statues found in their base.
- Mega Man:
- One of Shadow Man's stock ninja abilities (along with throwing lots and lots of shuriken and turning into a log when hit) in Mega Man 2: The Power Fighters is to summon a giant robot frog to ride on after reaching half health. His car in Mega Man: Battle & Chase is also shaped like a frog.
- The fangame Rockman 4 Minus Infinity invokes this trope even more by hiding a Bonus Boss fight against Shadow Man (along with his robot frog mount) in Toad Man's stage, while Toad Man suddenly becomes a lot more agile and ninja-like in his moveset.
- Persona 4 has Yosuke's initial Persona, the "disco ninja frog" Jiraiya.
- Pokémon X and Y: The fully evolved form of the Water-Type Starter Pokémon Froakie is the Water/Dark-Type Greninja. It wears its ninja influences on its sleeve with high attack and speed, a tongue which mimics a scarf and fashioning throwing stars out of water.
- When introduced as a playable character in Super Smash Bros. for Nintendo 3DS and Wii U, Greninja was granted several more ninja-like abilities. Along with the aforementioned Water Shuriken attack, it also gained a few moves in the form of water katanas (changed to water kunai as of Ultimate), and a Ninja Log counter-attack in the form of Substitute (which sometimes manifests as an actual log).
- Senran Kagura: In some games, one of Asuka's Ninja Arts is to summon a huge toad to slam onto multiple enemies.