Duvalia

Unlike other Plaga who burst from the neck, Duvalia Plagas will rip apart the host's entire upper body. They appear as shelled, flower-like parasites. Their weak point is the fleshy "tail" that hangs off their back (which is, in fact, the host's upper torso/ribcage), and the fleshy core of the shell, which is only exposed when the Duvalia is about to attack the player. In addition to these, and the usual weakness to bright light, Duvalia can be blown to pieces with a single hand grenade. A Duvalia has no arms and no jumping ability, making it one of the only foes in the entire game who cannot jump or climb.

In the Mercenaries minigame, the Duvalia gains the ability to jump across gaps and walk up stairs.

Duvalia can also be seen as a capsule-contained toy figure in the Resident Evil 5 bonus features.

Strategy

Use a Hand Grenade, instantly blowing it apart.
Use a Flash Grenade, that can instantly kill it.
Use a Rocket Launcher, instantly killing it.
Use a Proximity Bomb to instantly kill it
Before the Majini can transform into a Duvalia, it can be frozen solid with Nitrogen Rounds from the Grenade Launcher and shattered.
A Duvalia's legs can be fired upon repeatedly to make it kneel and open up its upper body, allowing a clear shot at its core. Even if the Duvalia has leg armor, the ankles and feet are still vulnerable.
Grenade Launcher Flash Rounds will instantly kill it with one shot.
If a Majini may turn into a Duvalia, it is prudent to shoot it in the legs and Neck Breaker or Throat Slit can be used.
If it is about to attack, an agent should quickly approach it from behind and strike using a Stun Rod, dealing instant death.

Attacks

Headbutt - Inflicts a moderate amount of damage.
Bite - Will send the player into the Dying stage. If a Duvalia bites the player a second time, it will remove the entire upper body (causing instant death).

The Mercenaries

It appears as a sub-boss in the Ancient Ruins and Experimental Facility.

The Mercenaries Reunion

Appears in every level except for The Mines and Missile Area.

Resident Evil: The Deck Building Game

Duvalia has been revealed as an Infected card in the Resident Evil DBG expansion, Alliance. Duvalia has an interesting effect; if it defeats a player, the player with the most decorations is given five "ammo x10" cards. This effect is meant to put the player in the lead at a slight disadvantage by giving them cards with minimal amounts of gold and ammo. Duvalia has 60 health, the same as Nemesis from the base set, and can deal 40 damge if the player does not defeat it.

Trivia

Duvalia refers to a species of plant found in Africa. It's most recognizable feature is a large bulb found inside five shorter appendages.
If a Base Majini is swelling with bubbles, it means it's going to turn into a Duvalia. However, this should not be confused with certain Base Majini who swell up and explode- The animation may be similar, but the result is radically different...
The first Duvalia can appear in the Marshlands in Chapter 3-1, after you get the Shaman slate. However this is very rare.
Since the pieces of flesh hooked to the torso cause the Duvalia pain when shot, it can be assumed that it may have opened the body forcefully but is still attached to all the nerves of the destroyed tissue.
Duvalia will appear only on Base Majinis or Wetlands Majinis who are infected with Type 3 Plagas.
The Duvalia has a similar look on the Tree of Madagascar also known as The man eating tree. A crytoid turned out to be a hoax tree that would feed on large animals and humans as well.