It isn't a common Entei... It is a Event Entei that was given a few days ago at Japan. There is also a Suicune(Sheer Cold, Air Slash, Aqua Ring, ExtremeSpeed) and Raikou (Aura Sphere, Zap Cannon, ExtremeSpeed, Weather Ball) with special moves.
Lol, srry.. I checked Serebii now and it says it can learn it on a special way witch I didn't know about... How do you actually get those moves on him? (I mean Entei and flare blitz and extremespeed)