The Phosbats are born from pods, they are even more vulnerable to light than their adult form and unlike them, they are vaporised if they are exposed to it for too long, if the pods are exposed to light, they will close to protect the Phosbats still incubating inside them. They are otherwise pretty slow and can be easily killed without trouble by a large group of Pikmin, they are themselves also often seen in groups to compensate for their weak letality. One point to note is that the Vehemoth Phosbat is fought alongside them, which make them more dangerous since they can more easily eat Pikmin when the captain are distracted by the huge flying beast.
An infinite will spawn in the Distant Tundra as long as at least one pod is still active.
They are the first hostile creatures encountered in Pikmin 3.