Why does the Alolan pokedex say such horrible things about mega evolution? My blazekin, Hina, gets a real thrill from the temporary power boost it gives, She eagerly taps her megastone when she goes into battle, and when she mega-evolves, she gives that particular cluck that she uses to mean “Good! Good!”

To be fair, the Alolan pokédex says horrible things about s lot of pokémon. That’s what happens when you let a ghost-type write the entries and an eccentric “approve” whatever it writes.

In all seriousness, though, mega evolution can be a highly stressful, extremely violent event. For most pokémon/trainer combinations, it takes time and effort to control the process, and only the extremely lucky or highly skilled master it right away.