
And because it's a Helmet Heroes bird, you know what that means...

TEABAGGING!!!
Immature joke aside, the Mushroom Bird would use Stun Spore, which does what you'd expect: paralyze its foes. Come on, if Scrap Bots can Touhou the heck out of players, Mushroom Birds can paralyze people. It also has a move that buffs its own defense and attack power by 30%. You know how I listed a damage formula that accounts for piercing damage? Here's what I got for monster defense buffs.
(Weapon Damage)*(Equipment Total)/(Monster Defense)²/Monster Defense Buff/(1-Piercing Damage)*5*Random(0.7;1.3)
As for Monster Attack Buffs...
Monster Power²*Monster Attack Buff/(Player Defense*Player Armor Total)*5*Random(0.7;1.3)
Yep. Now, for its info.:
Name: Mushroom Bird
HP: 750
Defense: 84
Power: 350
Weight: 60 lbs
Eliapedia Entry: Mushroom Birds are monstrous birds that reside in the Mushroom Borough. Since fungi usually tend to feed of dead things, the Mushroom Bird is largely a scavenger. Mushroom Birds are often found eating the remains of creatures ranging from swamp crabs and armed dillos to giants like the Gal Roach. Mushroom Birds can even handle scavenging off deceased Hellshags and Dumtilians despite the dangers of eating either creature. Despite their scavengerial nature, Mushroom Birds boast great power. A single Mushroom Bird can take down a military Stryker vehicle. Aside from raw power, Mushroom Birds are capable of spewing paralytic spores at its foes as a means of self-defense. It was once rumored that the Mushroom Bird housed all its organs inside the cap of its mushroom head, but dissection on Mushroom Birds later confirmed that this is completely false.
Drop List
Blue Beanie: $31; 10%; 3.1
Apple: $67; 10%; 6.7
Banana: $135; 10%; 13.5
Epee: $343; 5%; 17.15
Pizza: $472; 4%; 18.88
Long Bow: $700; 4%; 28
Stop Sign: $2540; 1%; 25.4
Moonlight Wand: $4096; 1%; 40.96
Feather Mantle: $9677; 0.5%; 48.385
Moonlight Staff: $15366; 0.25%; 38.415
Peacock Feathers: $142852; 0.1%; 142.582
Mushroom Plate Helmet: $2321062; 0.01%; 232.1062
Stage 3 Sharpening Stone: $3; ???
Stage 4 Sharpening Stone: $4; ???
Stage 2 Poison Rune: $2; ???
Total Loot Value: 615.1782
Yep. There ya have it. Enjoy.