101Leafy researched the games.
Hypno Whistle

Hunting Horn made from the Hypnocatrice. Not much for making noise. Causes Sleep.
| Class | Hunting Horn |
|---|---|
| Rarity | 9 |
| Attack | 884 |
| Sleep | 150 |
| Defense | +8 |
| Slots | 1 |
| Price | 80,000z |
Upgrades
| Upgraded from | Feather Whistle |
|---|---|
| Upgrades into | Hypno Slide Whistle |
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 738.
Materials
OrangeHypnoPelt+ ×8, Hypno Claw+ ×6, Eltalite Ore ×15, Hypno Bezoar+ ×1