Print the nth Fibonacci number containing the nth Fibonacci number!
Haskell, 85 84 bytes

EDIT:


-1 byte: Laikoni shortened l.
Typo (x&gt;=s for x&lt;=s) in explanation.


f takes an Int and returns a String.



l=0:scanl(+)1l
m=show&lt;$&gt;l
f n|x&lt;-m!!n=[y|y&lt;-x:m,or[x&lt;=s|s&lt;-scanr(:)""y,x++":"&gt;s]]!!n


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How it works


l is the infinite list of Fibonacci numbers, defined recursively as the partial sums of 0:1:l. It starts with 0 because lists are 0-indexed. m is the same list converted to strings.
In f:


n is the input number, and x is the (string of the) nth Fibonacci number.
In the outer list comprehension, y is a Fibonacci number tested for whether it contains x as a substring. The passing ys are collected in the list and indexed with the final !!n to give the output. An extra x is prepended to the tests to save two bytes over using !!(n-1) at the end.
To avoid counting ys several times, the tests of each y are wrapped in or and another list comprehension.
In the inner list comprehension, s iterates through the suffixes of y.
To test whether x is a prefix of s, we check whether x&lt;=s and  x++":"&gt;s. (":" is somewhat arbitrary but needs to be larger than any numeral.)