Unnamed Planet (Tiberius64)

First shown in Celestial Feelings, this planet is where Phineas and Isabella have one of their first semi-romantic moments near the end of the summer of 2011. It is later featured 29 years later (2040) in Ad Astra 5: The Fight for Ferb, where Phineas takes Ferb's body for revival from the death caused by his honorable sacrifice in Ad Astra 4: Sacrifice of the Angels.

Terrain
This planet is one described as "diverse" and "earth-like" in Celestial Feelings. It has varying climate zones, has an atmosphere with oxygen and free of toxins, and orbits a yellow star. The three terrains focused on are those of a beach, forest, and hilly region. The beach is featured in Celestial Feelings and Ad Astra 5, and is similar to earth beaches with sand bordering a salty body of water. There are some plants near the edge of the sand that are unique in form, such as small clusters of purple plants similar to berries and flowers, or slender and succulent dark green plants with bulbous ends at the ends of their stalks. The grass, however, is nearly identical to that of earth in appearance.

Another terrain featured is a forest, where there is much more unique flora. The grass and purple berry-like clusters are still present, but the tall and slender succulents are now as tall and thick as trees, there are now also thick tree-like growths with large berry-like growths from the top and thick vascular systems in the trunk, and tall blue stalky plants with a single large yellow bulb with orange spots between the two petals at the top. Many of these plants are revealed by S'lar to have medicinal properties that radically heal extreme oxidative stress on the body, as well as severe radiation damage of any sort. The final terrain given is a hill-filled region where Phineas fights a Karon captain in hand-to-hand combat, although nothing is mentioned about it beyond that.

Atmosphere
On top of an oxygen-filled atmosphere, there is another wonder that is found in the atmosphere alone. S'lar reveals in Ad Astra 5 that this planet to have a metaphasic radiation in the atmosphere with healing properties that also gives a physically youthful feeling to all exposed to it. It was the former effect that contributed to Phineas and Isabella coming closer together that late afternoon on the beach in 2011 and the latter that made it possible for Ferb to be revived after a death caused by radiation burns and poisoning in 2040.