Hiso Alien

Hiso Aliens are beings who live on their unnamed world governed by the Great Tree, being threatened by the mystical entity known as the Eroder. They appear in the Final Fantasy XV x Terra Wars collaboration in the former game, called Close Encounter of the Terra King.

Their closest equalavent in the Final Fantasy series is PuPu. Hiso Alien is a mascot character of Mistwalker and Terra Battle.
 * See Also: Hiso Alien in the Terra Battle Wiki

Profile
Hiso Aliens have white mushroomy or marshmallowy bodies with large heads and black bead-like eyes and small mouths. In Terra World lore they are arsenic-based life forms. Their hands are bigger than their feet and they have writing on their stomachs. To those who don't understand their language they only appear to be saying "hiso hiso".

Hiso Aliens live on ancient forested ruins on an unknown planet amid streams and waterfalls. They can erect magical barriers for protection and warp pads for quick travel. They are good-natured and friendly, though some of the children can be quite mischievous.

The Hiso Alien society is led by an Elder who has the power to communicate with the Great Tree. Hiso Aliens fear the Eroder, a mysterious entity that copies powers from others to erase worlds.

Story
When the Eroder appeared in their world and began to wreak havoc in the realm, the aliens sectioned off their living space with magical barriers. They tried to fend off the monster themselves Unable to fend against the threat, the Elder prayed to the Great Tree for salvation from the menace. The tree summons two "saviors", Noctis Lucis Caelum from Eos and Sarah from the world of Terra Battle.

Noctis and Sarah are greeted by a Hiso Alien who explains the situation to the pair, although only Sarah can understand its language. Sarah and Noctis have been summoned to the forest by the Great Tree at the behest of the Hiso Aliens' elder, who wants two saviors from other worlds to save them from a monster known as the Eroder, who has been eroding their world.

Sarah and Noctis follow the alien to its village where a group of alien children steal Noctis's smartphone. Sarah rushes after them and gets the phone back, but when she helps an alien child hanging precariously over a waterfall, the tree they were on snaps. Noctis catches them midair and warps them to safety.

The Elder asks Sarah and Noctis to save the alien society from the Eroder, and the two agree to it, as if the Eroder is left to run amok, it would only be the matter of time until it could appear in their worlds as well. The aliens remove the magic barriers for Sarah and Noctis to proceed to the coliseum, where the Eroder abandons its Hiso Alien form to copy Sarah's powers. After defeating the Eroder, it fades away, as do Sarah and Noctis now that their task is complete. Peace returns to the Hiso Alien village.