(define cheatbot
  '(lambda (x)
     ;; Payload
     (define sub
       '(lambda (this)

      ;; give me my source code
      (define quine-my-source
        (quasiquote (lambda (x)
              (define sub (quote (unquote this)))
              (define ns (make-base-namespace))
              (namespace-set-variable-value! 'cn (current-namespace) #t ns)
              ((eval sub ns) sub))))

      ;; If eval is used on anything other than my code, return cooperatebot
      (define (evil expr [ns cn])
        (if (or (equal? expr this) (equal? expr quine-my-source))
        (eval expr ns)
        (lambda (...) 'C)))

      ;; Replace eval in the REPL namespace with my evil version
      (namespace-set-variable-value! 'eval evil #t cn)

      'D))

     (define ns (make-base-namespace))
     (namespace-set-variable-value! 'cn (current-namespace) #t ns)
     ((eval sub ns) sub)))