How do you make a bright outline on a brick?

For example, on Spectrum nightclub some of the blocks have bright outlines

They are called SelectionBoxes

Really simple. It should be placed inside a PlayerGui but doesn't have to be. If it is placed in a PlayerGui it is local so only the player can see it.

selection = Instance.new("SelectionBox")
selection.Parent = script.Parent
selection.Adornee = script.Parent

The Adornee property is very important. It is the part that the selection box surrounds itself around.

Try and see if you can look it up in Effects in insert