They shoot out spiked balls that rain down upon the player.
Lungblossoms emit a hallucinogenic gas said to drive the weaker-willed insane. They remain still for the most part; they fire what is presumably fungus at whatever victim is within the proximity.
In Mt. Zand and the Strangers Dream, a more difficult lungblossom appears. They are slightly smaller than the traditional lungblossom, but have a vastly different attack pattern. Their projectile attack cannot be blocked and must be evaded. Constant movement is essential. Between the waves of fungus, attack the lungblossom with whatever weapons you have. Upgrades like Scumbag Tip (War Machete) and Napalm Reservoir (Fire Bellows) allow damage to be dealt whilst moving.
Lungblossoms don’t move, and fire relatively weak attacks. They are often accompanied by other beasts of the wild that make it harder to focus and block the rapid-fire attacks.
Counter-blocking is nearly useless. Since they don’t move and don’t deal damage on contact, you can stay close enough to attack it with a melee weapon, pausing to block whenever it fires. At the beginning of the battle, take out the things accompanying it.