A guide for items and what they do when you equip them. The who/when/where is left purposefully somewhat vague to try to keep things as spoiler-free as possible (Some are impossible to avoid due to how they are named, however).
Most of this guide is left purposefully vague so as to point you in the right direction without giving away the answer.
Day One <Text Adventure>
Picture = It does nothing <Trapdoor>
Note: As far as I can tell, this is a true statement. It appears to have no effect in battle during Day 2. During Day 1, I've tried many things : One cannot attach it to the fridge. I've tried giving it to most characters. It doesn't go on the quest board. Can't be put in the well, on the wall in the shed's basement, in the fountain.
Day 1 <Home/The North>
<Buddy>'s Breakfast = Slightly extends the duration of your block <Kitchen>
Coin = Every Party Member gets (+2) damage per basic attack <Tortley>
Rubber Duck = Whenever you befriend an enemy, heal for (+5) Friendship Points <Fountain>
Glass of Water = This is just plain water, but will boost your max Friendship Points by (+10) <Toot>
Toot's Tonic = Chance to apply the "Dumb & Dizzy" debuff at a random enemy at the start of combat <Toot> (You only get one on Day 2)
Umbrella = Start with the "Good Vibes" buff at start of combat <Toot's Pub>
Sa = Deal (+5) damage with your basic attack, but deal (+1) damage to a random teammate <Band Quest>
Dead Gwandma = Boost your max Friendship Points by (+20) <Scroobert>
Roller Skates = Your entire party moves faster outside of combat when walking around <Bean>
Can of Pears = Apply the "Awkward Silence" effect to a random enemy at the start of Combat <Bean>
Oats = Chance to apply the "Unconditional Love" effect to a random enemy at the start of combat <Grin>
Key = ??? <Metal Pile>
Battle Axe = Chance to reflect (+2) damage when attacked <Phoney>
Thing = Does not carry forward to Day 2 <Phoney>
Pinecone = When your friendship meter hits 0, instantly boost back up to full. Lose pinecone on use. <Phoney>
Spoiled Breakfast = Start with the "Butterflies" debuff at start of combat <Kitchen> (My assumption is that the equipped character starts with this debuff applied. I will test this at some point.)
Day 2 <Home/The North>
Pristine Apple = All party members heal (+2) at the start of their turn <Well>
Cool Hat = Start with the "Kudos" buff at the start of combat <Morton>
Flask of Unlimited Apple Juice = During your defense, heal (+2) for every attack you perfectly block <Toot>
<Cauldron Soup> = Chance for Rest to heal an extra (+5) Friendship Points <Cauldron>
The Very Berry = You start with the "Positive Attitude" buff at the start of combat <Scroobert>
Sarah's Running Shoes = Chance to negate half the damage taken when hit <France>
Lemon Pie of the Undead = Your Special Attack's Cooldown is reset at the start of battle <Rudy>
Severed Tongue = While equipped, you can store up to (4) compliments. <Phoney>
Timmy Quick Figurine = Reduces total cooldown for special attack by 1. <Bean>
Extremely Nice Letter = If equipped, all enemies will take an instant (+8) damage at start of battle. Lose extremely nice letter on use. <Arbor>
Beat Bomb = If a party member leaves with this equipped, deal (+20) damage to your attacker. Lose Beat Bomb on use. <Dejo Bravisa>
A Stick With Extra Length = While equipped, you will always attack first in battle <Grin>
Badge of Ultimate Friendship = Chance to apply the "Butterflies" debuff to a random enemy at the start of combat. <Lloyd>
Day 2 <<Palchum>Ville>
Pear Cake = Damage performed is doubled, but damage taken is also doubled. <Plapp>
The Dodecahedron = Your attacks do (+12) damage per status effect on this character. <Shape Gang>
Candle of Pure Loneliness = Chance to Apply "Insecure" debuff to a random enemy at the start of combat. (The Waxed Wick)
Gem of Confusing Perspective = Chance to Apply "Existential Crisis" debuff to a random enemy at the start of combat. (Candle of Pure Loneliness => Spotless Gems)
Larpo's Left Kidney = Extremely small chance to instantly befriend every enemy in combat. Yeah, it's that powerful. (Gem of Confusing Perspective => Stalefish)
Questionable Black Belt = When Friendship Points drop below 10, the "Emotional Barrier" buff is applied. Used only once per battle. (Larpo's Left Kidney => Cool Belts)
The Helmet of 7 Spikes = You start with the "Muscle Memory" buff at the start of combat (Questionable Black Belt => Iron Shield)
Eyepatch = Cosmetic only. Player only. Does not unequip currently equipped item. Equipped automatically. Is removed before player can engage in battle. Cannot be removed manually.
Additional Notes: Status Effects
- Awkward Silence = Afflicted character tells a joke. No one laughs. Afflicted character loses a turn
- Butterflies = Afflicted character's stomach is filled with butterflies. The butterflies try to escape. Afflicted character is damaged over time.
- Dizzy and Dumb = Afflicted character may miss attacks
- Existential Crisis = Afflicted has an existential crisis. They might hurt themselves instead of attacking for a few turns.
- Insecure = Afflicted starts to feel insecure in front of their friends. They'll take more damage for a few turns. How embarrasing.
- Stinky = Healing afflicted character causes that character damage instead of healing
- Unconditional Love = If afflicted character would damage the originator of debuff, that "damage" heals target instead of damaging them.
- Emotional Barrier = Affected character receives temporary bonus health
- Good Vibes = Affected character regenerates FP each round
- Kudos = Affected character will do double Damage on next turn (applies to all damage rolls : including multi-hit attacks/specials)
- Muscle Memory = Affected character has a chance for incoming damage to be halved
- Positive Attitude = Affected character will reflect damage reflection back onto attacker
Addendum: A character with Kudos has their base damage doubled BEFORE the effect of the Coin [EG : Bean => Base damage 7 => [7 x 2] + 2]. This is likely the case for other additive damage bonuses as well.
However it bears noting that this additive bonus is PER ATTACK in such cases. [EG : Bean has three hits per "basic attack" action => (7 + 2) x 3 = 27].
Similarly, the Dodecahedron's bonus applies per damage roll. So Bean's "Bean Mash," which has a base of 1, becomes 13 if one status effect is applied, [EG 1 + 12 = 13].
Due to the aforementioned "order of operations" for damage calculations, this damage is only 14 if that status effect is Kudos. [EG (1 x 2) +12 = 14).
- Cookie + Cookie = Raff Pudding <Kudos>
- Cookie + Canister = Meatloaf <Emotional Barrier>
- Cookie + Pepper = Eyeball Soup <Muscle Memory>
- Canister + Canister = Cauldron's Surprise <Positive Attitude>
- Canister + Pepper = Stuffed Bell Peppers <Good Vibes>
- Pepper + Pepper = Spicy Chicken Curry - <Heal 15 FP>