101Leafy researched the games.
Dragonhead Hammer

Large Bone Hammer with a shell made from a wyvern's skull. Beautiful and deadly.
| Class | Hammer |
|---|---|
| Rarity | 3 |
| Attack | 676 |
| Slots | 2 |
| Price | 2,600z |
Upgrades
| Upgraded from | Skullcrusher+ |
|---|---|
| Upgrades into | Ancient Relic, Basarios Blow |
Can also be made new at the smithy.
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 724.
Materials
Wyvern Skull Shl ×2, Lg Monster Bone ×3, Unknown Skull ×5, Killer Beetle ×10