Sunflora.
It converts sun light into energy. In the darkness after sunset, it closes its petals and becomes still.
Transcript
0:00What if I told you the happiest-looking Pokémon in Johto shuts off completely every single night, and almost nobody has ever seen it happen, because nobody is around.
0:07Spend a day with a Sunflora and you'll understand why everybody loves it.
0:14From the moment the sun's up, it's moving.
0:21The Pokédex says it rushes about in a hectic manner, and that's exactly right, it's the busiest thing in any field, face turned toward the sun the entire time, following it across the sky like the sun is a person it's been waiting all night to see.
0:28It's warmth on legs.
0:35The one everybody points at.
0:42If you had to draw a good mood, you'd draw this.
0:48BUT then the sun goes down, and the entries stop being cute.
0:55Sunflora comes to a complete stop.
1:02Not slows down, but like full STOP.
1:09It closes its petals and becomes still, and it stays that way, every night, until the light comes back.
1:16All of that energy was borrowed from the sky, and when the sky takes it back, there's nothing left to run on.
1:23The brightest thing in Johto spends every night as a closed flower in the dark, and the only reason you don't picture it that way is that nobody visits a field after dark.
Sp. Attack 105, Speed 30. Pick your poison.
Sunflora's base stat total is 425. The shape of a stat spread tells you everything about a Pokémon's role. Tanks lean defense, sweepers lean speed and attack.