Poo (うんち Unchi) is a recurring element that debuted on the original Tamagotchi and has appeared on every Tamagotchi pet since.
Poo resembles a small, dark mound with stink lines floating above it. Traditionally, poo always appears on the right side of the screen. On the Tamagotchi Connection Version 5 and related variations, poo appears on top of the screen instead.
On the Tamagotchi Angel, poo is made of solid gold, and the stink lines are replaced with sparkles. On the Tamagotchi Ocean, poo has no stink lines at all, but instead of sitting on the right side of the screen, it is stuck to the back of the pet until the user cleans it up.
Starting from the Mesutchi and Osutchi, baby characters would leave smaller poos than other characters.
On the Tamagotchi releases with color screens, the poos are yellow. When a Tamagotchi makes a second poo when there is one already on the screen, the existing poo will increase in size. If a Tamagotchi poops when it is sick, a black poo will appear.
On Tamagotchi 'Round The World, poo is a bright blue color and gradually gets darker for as long as it stays on the screen.
Throughout the day, a Tamagotchi will leave poo on the screen, and the user must clean it up using the Toilet icon. If left unchecked, multiple poos can appear on screen. If poo is present on the screen for too long, the Tamagotchi may get ill, which counts as a Care Mistake. On most versions, the hungry level drops by one heart when the Tamagotchi makes a poo.
On the Tamagotchi Angel, the pet would only poo after prayer, regardless whether or not the user praises them.
In the GameBoy game, a user could catch their Tamagotchi before it poos and, using the Toilet command, have it use a toilet instead of leaving the poo on the floor. This function was used on every Tamagotchi released afterwards, starting with the Tamagotchi Plus, although Ojitchi, Otokitchi and Oyajitchi could not use this.
On the TamaTown Tama-Go, if the user gives the Tamagotchi medicine when it reaches 99lbs, it will leave eight poos on the screen and it's weight will drop to 72lbs.
With the introduction of Tamacom, poo also functioned as a negative gift when a Tamagotchi gave a gift to another.
On Tamagotchi 'Round The World, poo is used to fertilize Gaiatchi plants. However, the player's Tamagotchi may poo on its own accord. If it leaves poo too close to a geyser, the rain dance must be performed to remove it.
In Tamagotchi L.i.f.e. Tap and Hatch, poo acted as a stage obstacle that falling blocks couldn't pass through. They could be cleared by either clearing a block directly touching it, or by using a Potty Bomb in the same row.
- In the Japanese commercials for the Tamagotchi GameBoy games, a recurring joke was that the characters could not make it through one commercial without leaving a poo.
- Unchi-Kun is a recurring character that resembles a golden poo with a face and limbs.
- Washikitchi carries a large poo on its back.
- On the Keitai Kaitsuu Tamagotchi Plus and Tamagotchi Connection Version 3, the first available game features the user avoiding falling poo while catching music notes. This is reversed on the Akai, where the user must catch poo of various sizes in trash cans and avoid the falling money.
- In the Run & Jump game on the Tamagotchi iD L, Mametchi must jump over the poo.