Blue Spike Ball
From Creatures Wikia
Blue Spike Balls are an artificial food source native to the Terra metaroom. These tasty spheres provide fat for creatures living in Terra, as this metaroom has no native flora which produces food, only plenty of fruit and seeds. The automatic creation of a steady supply of Blue Spike Balls can be turned off or on using the Terra Control panel. Blue Spike Balls are created on either side of the bridge, on the top level.
As an alternative, try introducing some Tuba plants as a natural food source.