Silver Walkers are upgraded versions of Black Walkers although they still go down in one shot. In Space Channel 5 Part 2, they appear three times. Their first debut is in "Report 5: The Spies Get Revenge!" as part of the trap Ulala and her friends must navigate. Their silhouettes appear on the walls and once 'chu' is said, they fully appear in whatever pose they took.
The second time these Robos are seen is in "Report 6: Purge's TV Special!" as part of the final wave with Bodyguards against Ulala and her companions. A total of 38 of these robots are destroyed by Ulala.
The third and final time is during the credits. Two boogie next to President Peace and over 200 of the little robots skip across the bottom of the screen.
"Surface is coated with solar metal for outer-space activity. They like to look at themselves in reflections on the shiny bodies of their robot pals." - in-game profile