Ruby/Method/remove method

my_array = Array.new
def my_array.random_dump(number)
  number.times { self << rand(100) }
end
p my_array.random_dump(3)
p my_array.random_dump(2)
p my_array                                      # => [6, 45, 12, 49, 66]
# That"s enough of that.
class << my_array
  remove_method(:random_dump)
end
my_array.random_dump(4)
# NoMethodError: undefined method "random_dump" for [6, 45, 12, 49, 66]:Array

class OneTimeContainer
  def initialize(value)
    @use_just_once_then_destroy = value
  end
  def get_value
    remove_instance_variable(:@use_just_once_then_destroy)
  end
end
object_1 = OneTimeContainer.new(6)
object_1.get_value
# => 6
object_1.get_value
# NameError: instance variable @use_just_once_then_destroy not defined
object_2 = OneTimeContainer.new("ephemeron")
object_2.get_value
# => "ephemeron"

class RandomizingArray < Array
  def <<(e)
    insert(rand(size), e)
  end
  def [](i)
    super(rand(size))
  end
end
a = RandomizingArray.new
a << 1 << 2 << 3 << 4 << 5 << 6           # => [6, 3, 4, 5, 2, 1]
p a[0]
p a[0]
p a[0]
p
class RandomizingArray
  remove_method("[]")
end
a[0]                                      # => 6
a[0]                                      # => 6
a[0]                                      # => 6