Slimamander appears as a three-headed creature resembling a reptile, with purple warty skin and blue lips with appendages resembling eyelashes on each of its mouths. Each mouth also sports a long pink yellow tipped drooling tongue, and out of any of them its single pink irised eye, which may pop out often. It has thick arms with four digits on each finger, and a indigo colored liquid seeps out of its body. Slimamander is actually seen coiled with said seeping liquid.
In the Japanese version of the game, Slimamander ends all sentences with "gyoro" (ギョロ), basically being a eye glare sound effect.
Slimamander has the ability to swap the placement of his single eye that he has in his mouth.
He also has the ability to breathe fire from his mouths.
Accept the quest Seal No Evil, which is located in Shopper's Row (it should be outside of the Everymart). If the quest isn't there, then you may have to rank up your watch to at least Rank B, or you may also need to complete the Ghost Club at School quest. You do not have to complete the game or have entered the Infinite Inferno to activate this quest. This quest is exclusive to Bony Spirits only.
Go to where you are supposed to (which is right outside of the school, where you first fought him) for the quest, and save right before you fight Slimamander.
Try bringing a Superstar Soul or a Yo-kai with the Popularity ability (Shmoopie, Cupistol, etc.). Even though he is a boss, it can slightly increase your chances of befriending him.
If you don't get him the first time, soft reset the game, and continue fighting him until his dialogue changes after fighting him and you get his medal. Unlike other Yo Kai he will befriend you judging on how good you battled, for example if you keep needing to heal every turn then he probably won't befriend you.It is recommended to try with at least a level 30 to 35 team. He won't approach you and instead talk to you before giving his medal.
Slimamander, along with Sproink, and SV Snaggerjag could all be befriended in their boss stages in the Befriend-a-Boss event. During the event their fusion items were found in the Crank-a-kai which turned them into their S rank forms.
The only way to damage Slimamander is to target the mouth in which its eye resides. The method to do this is to damage the heads until they open their mouth; therefore Soultimate Moves that attack multiple targets are extremely helpful.
After a while, Slimamander will close its open mouths and reposition its eye, requiring you to repeat the above pattern.
After daily battle (Befriending): "You're really strong! Let's be friends. If I can stick with you, I can really let loose. Please. Take me with you! [...] Heh. I'm looking forward to fighting together in the future..."
His Japanese name, "Mitsumata Nozuchi", translated as "three-pronged wild hammer" (Japanese: 三叉野槌,Mitsumata Nozuchi). His English name, "Slimamander", is a portmanteau of slime and salamander.
Slimamander is based on the nozuchi (Japanese: 野槌,nozuchi "wild hammer"), a snake-like youkai with a thick, hairy body resembling a mallet in shape, and no features on its head save for a large mouth (though sometimes, nozuchi have tiny eyes). It feeds on small wildlife and travels down the mountains it inhabits by biting on its tail and tumbling down slopes. It's very aggressive towards humans, and will roll down onto anyone disturbing its nest and inflict a nasty, painful bite on them.
This youkai is one of Japan's most ancient youkai species, being among the first mentioned in recorded history, though the nozuchi is considered to be more of a mountain kami than an actual youkai.