In Gold, Silver and Crystal only, Shuckle could randomly make Berry Juice by holding a berry after winning a battle.
Let's implement it back!

In `src_battle_script_commands.c`, search for the function `Cmd_pickup` and below both instances of `if (ability == ABILITY_PICKUP`, add the following block:

```diff
static void Cmd_pickup(void)
{
    s32 i;
    u16 species, heldItem;
    u8 ability;

    if (InBattlePike())
    {

    }
    else if (InBattlePyramid())
    {
        for (i = 0; i < PARTY_SIZE; i++)
        {
            species = GetMonData(&gPlayerParty[i], MON_DATA_SPECIES2);
            heldItem = GetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM);

            if (GetMonData(&gPlayerParty[i], MON_DATA_ABILITY_NUM))
                ability = gBaseStats[species].abilities[1];
            else
                ability = gBaseStats[species].abilities[0];

            if (ability == ABILITY_PICKUP
                && species != 0
                && species != SPECIES_EGG
                && heldItem == ITEM_NONE
                && (Random() % 10) == 0)
            {
                heldItem = GetBattlePyramidPickupItemId();
                SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
            }
+           else if (species == SPECIES_SHUCKLE
+               && heldItem >= FIRST_BERRY_INDEX
+               && heldItem <= LAST_BERRY_INDEX)
+           {
+               if (!(Random() % 16))
+               {
+                   heldItem = ITEM_BERRY_JUICE;
+                   SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
+               }
+           }
        }
    }
    else
    {
        for (i = 0; i < PARTY_SIZE; i++)
        {
            species = GetMonData(&gPlayerParty[i], MON_DATA_SPECIES2);
            heldItem = GetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM);

            if (GetMonData(&gPlayerParty[i], MON_DATA_ABILITY_NUM))
                ability = gBaseStats[species].abilities[1];
            else
                ability = gBaseStats[species].abilities[0];

            if (ability == ABILITY_PICKUP
                && species != 0
                && species != SPECIES_EGG
                && heldItem == ITEM_NONE
                && (Random() % 10) == 0)
            {
                s32 j;
                s32 rand = Random() % 100;
                u8 lvlDivBy10 = (GetMonData(&gPlayerParty[i], MON_DATA_LEVEL) - 1) / 10;
                if (lvlDivBy10 > 9)
                    lvlDivBy10 = 9;

                for (j = 0; j < (int)ARRAY_COUNT(sPickupProbabilities); j++)
                {
                    if (sPickupProbabilities[j] > rand)
                    {
                        SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &sPickupItems[lvlDivBy10 + j]);
                        break;
                    }
                    else if (rand == 99 || rand == 98)
                    {
                        SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &sRarePickupItems[lvlDivBy10 + (99 - rand)]);
                        break;
                    }
                }
            }
+           else if (species == SPECIES_SHUCKLE
+               && heldItem >= FIRST_BERRY_INDEX
+               && heldItem <= LAST_BERRY_INDEX)
+           {
+               if (!(Random() % 16))
+               {
+                   heldItem = ITEM_BERRY_JUICE;
+                   SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
+               }
+           }
        }
    }

    gBattlescriptCurrInstr++;
}
```

And that's it!

~AsparagusEduardo