Plasma and meteors are impassable terrain which appear in Advance Wars: Days of Ruin.
Plasma and meteors don't give any terrain stars.
An non-specified amount of time before the start of Days of Ruin, meteors fell to the ground and nearly wiped out the planet's population. A side-effect was that some started giving off plasma.
Plasma and meteors cannot be crossed by any units. However, meteors can be attacked. If a meteor is destroyed, any plasma that is connected to it disappears. After the meteor is gone, any land below the plasma or meteor turns into a plains tile. However, the damage that having the meteor/plasma above it is clearly visible. Unlike the similar terrain pipes from the previous games, they can also be found over seas, and once the plasma and meteors are cleared from the area they are replaced by normal sea tiles. Unlike over land, the damage isn't visible.