The Mushroom of Time

Toshi no kazu dake (年の数だけ) is the 347th chapter of the manga and the first chapter of the Mushrooms of Time Arc.

Ryoga has gotten himself lost once again, this time in a strange forest. After searching in vain for food, he has to settle for eating a single, puny mushroom for dinner. After swallowing it a man jumps out of the bushes and begs him not to eat it. Days later Ranma comes across P-chan who is growing some mushrooms in a bowl. Ranma tries to eat one, but Ryoga stops him after splashing himself with hot water. Ranma is shocked to find that Ryoga has de-aged and is now a small child.

The Mushrooms of Time
After getting lost in a strange forest for three days, Ryoga's food supplies have finally run out, forcing him to make a meal out of a small mushroom. But just as Ryoga puts the Mushroom in his mouth, a man jumps out from behind him and tells Ryoga not to eat the Mushroom.

Unfortunately, the man pushed Ryoga whilst warning him which caused him to swallow the Mushroom. Seeing that Ryoga's already swallowed the Mushroom, the man reassures him that it isn't poisonous, but adds that he might wish he was dead as terrible things happen to whoever eats Mushrooms from this forest. The man continues by noting that the first symptom is the heart going "thump" before "she-bang" and no sooner does the man note these symptoms than does Ryoga experience them...

Three days pass and Ranma finds P-chan boiling some water in a local park. Ranma then notices the Mushrooms which P-chan has with him and assumes that this must be his (Ryoga's) lunch. As Ranma goes in to eat one of the Mushrooms, P-chan does his best stop Ranma, but is ultimately forced to turn back into his human form so that he can throw a medium-sized rock into Ranma's mouth.

After removing the rock Ranma prepares to fight Ryoga, but is shocked to see a de-aged Ryoga standing in his place. Ranma then plays dumb and goes off to find Ryoga, although the now agitated Ryoga calls him back so that he can explain himself.

Once Ryoga covers himself with one of his now oversized shirts, Ryoga explains to Ranma that the Mushrooms are called "Mushrooms of Time" and that the age whoever eats them will change to the height of the Mushroom (ex. a 5cm Mushroom makes you 5 years-old whilst a 10cm one makes you 10 years-old), so he needs to eat a 16cm Mushroom in order to return to normal. Ryoga then proceeds to walk off as he can't afford for anyone to see him this way, but Ranma easily stops the pint-sized Ryoga and tells him that he can return to the Tendo Dojo with him. Ryoga is shocked by Ranma's generosity, although Ranma reassures him to not be so foolish.

Growing More Mushrooms
Upon returning to the Dojo, however, Ranma immediately declares the de-aged Ryoga to actually be Ryoga's son. Despite Ryoga's protests, Akane and Nabiki note the (obvious) resemblance to Ryoga, but can't believe that Ryoga managed to find a girl or have the courage to have a child with her. Having had enough of the wild rumours, Ryoga hits Ranma with his Umbrella, prompting Nabiki to comment of what a violent brat he is.

A little while later and Ranma starts looking for a dark, humid place and notices a sign on the bathroom door which notes that it's out of order. After looking inside, Ranma thinks he's found the perfect place for the Mushrooms and puts them in the covered over bath so they can grow. However, after Ranma leaves, Soun passes and notices the sign and realises he forgot to remove it before prompting doing so.

Meanwhile, Ryoga has just finished getting changed into some of Akane's old clothes from when she was younger. After Akane comments on how cute Ryoga is while he becomes overjoyed at the thought of being in Akane's clothes, Akane asks the pint-sized Ryoga to give her a hug. Ryoga immediately panics and tries to turn down the offer, but soon gives in and sits on Akane's lap before she gives him a loving hug. Seeing that Ryoga is in his heaven, Ranma decides to intervene by playing human windmill with Ryoga before throwing him into the air - causing Ryoga to hit the ceiling.

After Akane hits Ranma with a mallet for bullying little Ryoga, Ryoga himself quietly decides that his life might not be that bad as a child before thinking that he should take advantage of the situation while he waits for the Mushrooms to grow. At that moment, however, Soun returns and is overjoyed at seeing a little boy (having only ever had daughters) and wastes no time in hugging Ryoga and giving him a "moustache rub". As Ranma looks on at Ryoga's suffering, the mortified Ryoga decides he must change back as soon as possible.

That Evening
Some time later and Kasumi tells Akane that it's time she took her bath. Hearing this, Akane asks Ryoga if he wants to have a bath with her so she can wash his back. Ryoga is initially against the idea, but quickly gives in to the thought of him sharing a bath with Akane until Ranma intervenes again and tells him that there's no way that's going to happen.

Ryoga then proceeds to kick Ranma in the leg before running off with Ranma in pursuit. Ranma, however, is soon overpowered by Ryoga when he uses his Shishi Hōkōdan before declaring he's going to take his bath with Akane. Suddenly Ranma recalls that the bath was meant to be broken and follows Ryoga to the bathroom where the pair discover the now ruined Mushrooms floating in the water.

Devastated, Ryoga warns Ranma that although in ten years he'll be the same as before, until then he's going to make his life a living hell. The pair then begin fighting each other and the ensuing noise attracts the attention of the other Dojo residents. However when they get near the door, Ryoga uses another Shishi Hōkōdan which sends a de-aged Ranma flying through the door and into Akane's arms. As the Tendo sisters look on in confusion, Ranma curses Ryoga for what he did while Ryoga sobs at the loss of his Mushrooms.

Cast in Order of Appearance

 * Ryoga Hibiki (human)
 * Mushroom Farmer (debut)
 * Ranma Saotome (male)
 * Ryoga Hibiki (P-chan)
 * Akane Tendo
 * Kasumi Tendo
 * Nabiki Tendo
 * Soun Tendo
 * Genma Saotome (panda)