Predicting random numbers based on past output
You need to find or create a Mersenne Twister rainbow table. In other words, pre-compute all (or some subset) possible outputs, store them (time-space tradeoff), and compare the series you receive to the stored series.

The article quoted in https://stackoverflow.com/questions/6618836/how-if-at-all-does-a-predictable-random-number-generator-get-more-secure-after suggests the number of values you need to store may be much smaller.