|Home world:||Planet Earth (Nebula M78 Universe)|
|First appearance:||Return of Ultraman Episode 34: "The Life That Can't Be Forgiven" (1971)|
Subtitle: Compatibility Monster (合性怪獣 Aishō Kaijū)
- Length: 2m - 50 m
- Height:2m - 30 m
- Weight: 28,000 t
- Origin: Mizuno Biological Laboratories (Hakone Lake)
Dr. Mizuno, a scientist that pushed the boundaries of biology and an old friend of Hideki Go, wanted to mix animal and plant DNA for science. The result was the monster Leogon, who was born from an egg in his laboratory. However, something went wrong, as Leogon quickly escaped and grew from two feet long to the size of a rhinoceros within a minute. MAT quickly tracked Leogon down to a lake where they attacked him. MAT did little except annoy the hybrid organism as his vines easily entangled them in midair. Hedeki wanted to end the madness before someone was killed and quickly turned into Ultraman Jack. The two giants clashed, but Jack quickly outmatched Leogon and finished him off with the Ultra Spark, slicing him to pieces.
- Leogon's roar is a recycled Zambolar roar.
- Designer: Maiya Jia Akira.
- Leogon shares several traits with the Toho kaiju Biollante, as both of them were created by the same man: Shinichiro Kobayashi. Both kaiju are plant-animal hybrids that appear in stories with a "science gone too far" theme. Interestingly, Leogon was designed by concept artist Kako Yodane, who also submitted initial concept designs for Biollante to Toho, which are compiled in the book Godzilla vs. Biollante Completion. In Yodane's own 2014 art book, he revealed that his final form Biollante concept art was inspired directly by Leogon.
- Curiously, the location where Jack and Leogon fight is the same location where Godzilla and Biollante fight for the first time, in Lake Ashi.
- Although not physically seen, Leogon is one of the monsters that makes up Beryudora's Body in Mega Monster Battle: Ultra Galaxy Legend The Movie.
Powers and Weapons
- Growth: Leogon can grow from two feet long to 157 feet long in a matter of hours.
- Adept Swimmer: Leogon can swim through water at low speeds.
- Vine Tentacle: Leogon can use two large vines like tentacles from the tubes on his back. These tentacles are ideal for wrapping around targets.
|Return of Ultraman Kaiju & Seijin|
|Takkong | Zazahn | Arstron | Sadola | Detton | Kingsaurus III | Gudon | Twin Tail | Gorbagos | Ghostron | Dangar | Stegon | Mognezun | Shugaron | Seamons | Seagorath | Eledortus | Terochilus | Bemstar | Sartan | Magnedon | Beacon | Gokinezula | Zanika | Vacuumon | Kupukupu | Kingstron | Zagorath | Nokogilin | Gronken | Varricane | Yadokarin | Oxter | Plooma | Alien Zelan | King Maimai | Alien Mates | Muruchi | Leogon | Pris-Ma | Draculas | Re-Seagorath | Re-Bemstar | Black King | Alien Nackle | Alien Varduck | Alien Black | Snowgon | Alien Baltan. Jr | Builgamo | Alien Stora | Paragon | Alien Grotes | Kodaigon | Granadas | Alien Centaurus | Robonez | Alien Cygnus-61 | Alien Messie | Alien Zoole | Red Killer | Femigon | Yametaranese | Sasahiller | Alien Ateria | Alien Mysteler | King Bockle | Alien Bat | Zetton II|