The organism that has mitochondria with disc-shaped cristae is the protozoan *Trypanosoma brucei* . This is a fascinating example of how the structure of mitochondria can be adapted to the specific needs of an organism.

Here's why this is interesting:

* Typical cristae: Most eukaryotic organisms have mitochondria with cristae that are folded into shelf-like structures. These folds increase the surface area of the mitochondrial membrane, which is important for the production of ATP (the cell's energy currency).

* Unique adaptation: In *Trypanosoma brucei*, the disc-shaped cristae are likely an adaptation to the parasitic lifestyle of this organism. It's believed that these disc-shaped cristae may help to increase the efficiency of energy production in the harsh environments where these parasites live.

Let me know if you'd like to learn more about the unique adaptations of *Trypanosoma brucei*!