All of the answers are names of Ice-type pokemon, either legendary or in their highest (or only) evolutionary form.
Across
1. A wily Dark pokemon that hunts in packs. It slices with its wicked claws.
4. A legendary Dragon that fell to Earth in a meteorite, according to Unova legends.
7. A large blue pokemon known for ferrying people across the waters of Kanto.
8. A walrus-like pokemon that hails from Hoenn. It is blue and white.
11. A snowflake-like pokemon that attacks by whipping its icy chains.
16. A penguin-like pokemon that stores food in its tail.
18. A large brown pokemon with giant tusks. In the anime, Dawn has one.
Down
2. A large Grass type from Sinnoh, where it is known as the Abominable Snowman.
3. A ghostly pokemon that is always female. It evolved using a Dawn Stone.
5. A strange pokemon that resembles a double-scoop ice cream cone.
6. A legendary bird of Kanto that causes snow to fall wherever it flies.
9. A Psychic type that puts opponents to sleep with a kiss.
10. A round pokemon with black spikes for horns. It can float and manipulate ice.
12. Eevee evolves into this pokemon when you level it up near an ice-covered rock.
13. A legendary golem of Hoenn. It cannot melt, even if it is submerged in hot magma.
14. This bivalve with a spiky shell was evolved using a Water Stone.
15. A large ursine pokemon that makes fangs and claws out of ice by freezing air.
17. A pure white pokemon with a flowing tail. It bashes icebergs apart with its horn.
