G-Pod
NOTE: SPOILERS
The G-Pod is the name given to the Government Pod that bears a resemblance to the Research Pod. It is colored chrome and has a large metal claw that hangs beneath it. The claw is used to lift up objects for transport. In Pikmin 3 it is seen delivering a message to the President of Hocotate Freight in the opening sequence, as well as "upgrading" the Hocotate Ship (which is soon revealed to be a program that keeps the ship on the planet until all the treasures are collected) so it has other functions besides heavy-duty lifting, apparently.
In Combat
At a certain point late in the game Olimar and Louie will have to confront G-Pods. They aren't native to the planet so they aren't featured in the Piklopedia. They don't move quickly at all and are pretty easy to fight, but you'll want to avoid their attacks nonetheless. The first is not deadly but it is annoying. They drag the claw along the ground to trip up Pikmin and pilots. Just swarm your Pikmin out of the way. The other is a quick burst of laser shots that might kill a few Pikmin. This is what makes G-Pods dangerous. In order to defeat one, toss up Yellow Pikmin and they'll pull it to the ground once they hold the propellor in place. Then throw Purple Pikmin at it to smash it apart. G-Pods may swoop by with their claw and attempt to take nearby treasures and fly around with them, so that's another reason to get them out of the way.
Trivia
A trick way (and much cooler) to take out G-Pods is to use the seemingly useless "Nap" ability with no Pikmin nearby. The G-Pod will pick the pilot up in its claw and stow the pilot within its hull. Once the pilot is in, have him wake up and then punch a few times. The G-Pod will burst to pieces in midair, taking out any nearby G-Pods as well. The pilot will be unharmed.