Small Script (R15)

function PlayerSize(player)
        local SizeValue = 0.5

        local humanoid = player.Character.Humanoid
        if humanoid then
              if humanoid:FindFirstChild("BodyHeightScale") then
                  humanoid.BodyHeightScale.Value = SizeValue
              end
              if humanoid:FindFirstChild("BodyWidthScale") then
                  humanoid.BodyWidthScale.Value = SizeValue
              end
              if humanoid:FindFirstChild("BodyDepthScale") then
                  humanoid.BodyDepthScale.Value = SizeValue
              end
              if humanoid:FindFirstChild("BodyHeadScale") then
                  humanoid.BodyHeadScale.Value = 1
              end
       end
end

wait(1)
PlayerSize(game.players.LocalPlayer)