broken.rb

class BrokenNumber
  def initialize(num)
    @num = num
  end

  def method_missing(m, *a, &b)
    @num.send(m, *a, &b)
  end

  def coerce(other)
    [self, self]
  end
end

x.txt

>> require "./broken"
=> true
>> x = BrokenNumber.new(2)
=> #<BrokenNumber:0x007f832b9a9880 @num=2>
>> 2 + x
SystemStackError: stack level too deep
...
>> 2 + x
Segmentation fault: 11