A guy in Japan got a Vaporen with CP 2048 by evoving an Eevee with CP 781. He found the best Eevee after catching more than 40 Eevees. Since CP decides stats of Pokemon with except of HP in Pokemon Go, the Vaporen he got is the best Vaporen he has ever seen.
1, Caught a lot of Eevees
The Japanese guy, who got a Vaporen with CP 2048, capture over 40 Eevees to find the one with the highest CP.
2. Eevee with CP 781
Finally he got the Eevee having 781 CP. It is very high CP. He was very happy and named it a 'Rising star'.
3. Evolving the Eevee into a Vaporen
The Eevee evolved into the Vaporen successfully. It has 2048 CP, and the value is very high. The Pokemon also has Water Gun as a fast move and Aqua Tail as a charge move.
He decided to evolve the Eevee into a Vaporen to see how many CP it will have. To choose what the Eevee evolves into, he used a trick, renaming the Eevee 'Rainer' before evolving it. If you want to know the details of the tip, see the link below.