The Phoenix's Favorite (大トリの好物, Otori no Daibutsu, lit. Phoenix's Favorite Food) is an event in Tomba!.
Feed Bunk Flowers to the Phoenix to make it well again. This will allow you to travel to the Masakari Jungle.
The Phoenix is on top of the Phoenix nest, upon completion of the Lava Caves. You can find Bunk Flowers inside the Lava Caves. You will need at least 5 of these (even though there are 6) to make the Phoenix well. It should trigger the event completion when you have enough.