diff --git a/redbot/core/bot.py b/redbot/core/bot.py
index 9b1fb7b5c..d16f30070 100644
--- a/redbot/core/bot.py
+++ b/redbot/core/bot.py
@@ -7,6 +7,7 @@ from importlib.machinery import ModuleSpec
 from pathlib import Path
 
 import discord
+import sys
 from discord.ext.commands.bot import BotBase
 from discord.ext.commands import GroupMixin
 from discord.ext.commands import when_mentioned_or
@@ -268,9 +269,15 @@ class RedBase(BotBase, RpcMethodMixin):
                 pass
         finally:
             # finally remove the import..
+            pkg_name = lib.__package__
             del lib
             del self.extensions[name]
-            # del sys.modules[name]
+            for m, _ in sys.modules.copy().items():
+                if m.startswith(pkg_name):
+                    del sys.modules[m]
+
+            if pkg_name.startswith('redbot.cogs'):
+                del sys.modules['redbot.cogs'].__dict__[name]
 
     def register_rpc_methods(self):
         rpc.add_method('bot', self.rpc__cogs)
diff --git a/redbot/core/config.py b/redbot/core/config.py
index b5e1825e1..03d9c0d46 100644
--- a/redbot/core/config.py
+++ b/redbot/core/config.py
@@ -1,7 +1,5 @@
-import contextlib
 import logging
 import collections
-from weakref import ref
 from copy import deepcopy
 from typing import Union, Tuple
 
@@ -418,10 +416,6 @@ class Group(Value):
         await self.driver.set(*self.identifiers, *path, value=value)
 
 
-_config_cogrefs = {}
-_config_coreref = None
-
-
 class Config:
     """Configuration manager for cogs and Red.
 
@@ -470,7 +464,6 @@ class Config:
         self.unique_identifier = unique_identifier
 
         self.driver = driver
-        self.driver.unique_cog_identifier = self.unique_identifier
         self.force_registration = force_registration
         self._defaults = defaults or {}
 
@@ -483,6 +476,13 @@ class Config:
                  force_registration=False, cog_name=None):
         """Get a Config instance for your cog.
 
+        .. warning::
+
+            If you are using this classmethod to get a second instance of an
+            existing Config object for a particular cog, you MUST provide the
+            correct identifier. If you do not, you *will* screw up all other
+            Config instances for that cog.
+
         Parameters
         ----------
         cog_instance
@@ -514,11 +514,6 @@ class Config:
         cog_name = cog_path_override.stem
         uuid = str(hash(identifier))
 
-        with contextlib.suppress(KeyError):
-            conf = _config_cogrefs[cog_name]()
-            if conf is not None:
-                return conf
-
         # We have to import this here otherwise we have a circular dependency
         from .data_manager import basic_config
 
@@ -529,12 +524,11 @@ class Config:
 
         log.debug("Using driver: '{}'".format(driver_name))
 
-        driver = get_driver(driver_name, cog_name, data_path_override=cog_path_override,
+        driver = get_driver(driver_name, cog_name, uuid, data_path_override=cog_path_override,
                             **driver_details)
         conf = cls(cog_name=cog_name, unique_identifier=uuid,
                    force_registration=force_registration,
                    driver=driver)
-        _config_cogrefs[cog_name] = ref(conf)
         return conf
 
     @classmethod
@@ -550,10 +544,6 @@ class Config:
             See `force_registration`.
 
         """
-        global _config_coreref
-        if _config_coreref is not None and _config_coreref() is not None:
-            return _config_coreref()
-
         core_path = core_data_path()
 
         # We have to import this here otherwise we have a circular dependency
@@ -562,12 +552,11 @@ class Config:
         driver_name = basic_config.get('STORAGE_TYPE', 'JSON')
         driver_details = basic_config.get('STORAGE_DETAILS', {})
 
-        driver = get_driver(driver_name, "Core", data_path_override=core_path,
+        driver = get_driver(driver_name, "Core", '0', data_path_override=core_path,
                             **driver_details)
         conf = cls(cog_name="Core", driver=driver,
                    unique_identifier='0',
                    force_registration=force_registration)
-        _config_coreref = ref(conf)
         return conf
 
     def __getattr__(self, item: str) -> Union[Group, Value]:
@@ -1003,7 +992,7 @@ class Config:
 
         """
         if not scopes:
-            group = Group(identifiers=(self.unique_identifier, ),
+            group = Group(identifiers=[],
                           defaults={},
                           driver=self.driver)
         else:
diff --git a/redbot/core/drivers/red_base.py b/redbot/core/drivers/red_base.py
index c92d7dabb..38b8bb14f 100644
--- a/redbot/core/drivers/red_base.py
+++ b/redbot/core/drivers/red_base.py
@@ -2,9 +2,9 @@ __all__ = ["BaseDriver"]
 
 
 class BaseDriver:
-    def __init__(self, cog_name):
+    def __init__(self, cog_name, identifier):
         self.cog_name = cog_name
-        self.unique_cog_identifier = None  # This is set by Config's init method
+        self.unique_cog_identifier = identifier
 
     async def get(self, *identifiers: str):
         """
diff --git a/redbot/core/drivers/red_json.py b/redbot/core/drivers/red_json.py
index 5471d4246..348cb44bc 100644
--- a/redbot/core/drivers/red_json.py
+++ b/redbot/core/drivers/red_json.py
@@ -1,5 +1,7 @@
 from pathlib import Path
 from typing import Tuple
+import weakref
+import logging
 
 from ..json_io import JsonIO
 
@@ -8,6 +10,28 @@ from .red_base import BaseDriver
 __all__ = ["JSON"]
 
 
+_shared_datastore = {}
+_driver_counts = {}
+_finalizers = []
+
+log = logging.getLogger("redbot.json_driver")
+
+
+def finalize_driver(cog_name):
+    if cog_name not in _driver_counts:
+        return
+
+    _driver_counts[cog_name] -= 1
+
+    if _driver_counts[cog_name] == 0:
+        if cog_name in _shared_datastore:
+            del _shared_datastore[cog_name]
+
+    for f in _finalizers:
+        if not f.alive:
+            _finalizers.remove(f)
+
+
 class JSON(BaseDriver):
     """
     Subclass of :py:class:`.red_base.BaseDriver`.
@@ -20,9 +44,9 @@ class JSON(BaseDriver):
 
         The path in which to store the file indicated by :py:attr:`file_name`.
     """
-    def __init__(self, cog_name, *, data_path_override: Path=None,
+    def __init__(self, cog_name, identifier, *, data_path_override: Path=None,
                  file_name_override: str="settings.json"):
-        super().__init__(cog_name)
+        super().__init__(cog_name, identifier)
         self.file_name = file_name_override
         if data_path_override:
             self.data_path = data_path_override
@@ -35,6 +59,26 @@ class JSON(BaseDriver):
 
         self.jsonIO = JsonIO(self.data_path)
 
+        self._load_data()
+
+    @property
+    def data(self):
+        return _shared_datastore.get(self.cog_name)
+
+    @data.setter
+    def data(self, value):
+        _shared_datastore[self.cog_name] = value
+
+    def _load_data(self):
+        if self.cog_name not in _driver_counts:
+            _driver_counts[self.cog_name] = 0
+        _driver_counts[self.cog_name] += 1
+
+        _finalizers.append(weakref.finalize(self, finalize_driver, self.cog_name))
+
+        if self.data is not None:
+            return
+
         try:
             self.data = self.jsonIO._load_json()
         except FileNotFoundError:
@@ -65,8 +109,11 @@ class JSON(BaseDriver):
         try:
             for i in full_identifiers[:-1]:
                 partial = partial[i]
-            del partial[identifiers[-1]]
+            del partial[full_identifiers[-1]]
         except KeyError:
             pass
         else:
             await self.jsonIO._threadsafe_save_json(self.data)
+
+    def get_config_details(self):
+        return
diff --git a/redbot/core/drivers/red_mongo.py b/redbot/core/drivers/red_mongo.py
index 61593ffe3..bba59fe71 100644
--- a/redbot/core/drivers/red_mongo.py
+++ b/redbot/core/drivers/red_mongo.py
@@ -32,8 +32,8 @@ class Mongo(BaseDriver):
     """
     Subclass of :py:class:`.red_base.BaseDriver`.
     """
-    def __init__(self, cog_name, **kwargs):
-        super().__init__(cog_name)
+    def __init__(self, cog_name, identifier, **kwargs):
+        super().__init__(cog_name, identifier)
 
         if _conn is None:
             _initialize(**kwargs)
@@ -105,10 +105,15 @@ class Mongo(BaseDriver):
         dot_identifiers = '.'.join(identifiers)
         mongo_collection = self.get_collection()
 
-        await mongo_collection.update_one(
-            {'_id': self.unique_cog_identifier},
-            update={"$unset": {dot_identifiers: 1}}
-        )
+        if len(identifiers) > 0:
+            await mongo_collection.update_one(
+                {'_id': self.unique_cog_identifier},
+                update={"$unset": {dot_identifiers: 1}}
+            )
+        else:
+            await mongo_collection.delete_one(
+                {'_id': self.unique_cog_identifier}
+            )
 
 
 def get_config_details():
diff --git a/tests/conftest.py b/tests/conftest.py
index af102e2e1..a3ad0919a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -38,6 +38,7 @@ def json_driver(tmpdir_factory):
     path = Path(str(tmpdir_factory.mktemp(rand)))
     driver = red_json.JSON(
         "PyTest",
+        identifier=str(uuid.uuid4()),
         data_path_override=path
     )
     return driver
@@ -45,10 +46,9 @@ def json_driver(tmpdir_factory):
 
 @pytest.fixture()
 def config(json_driver):
-    import uuid
     conf = Config(
         cog_name="PyTest",
-        unique_identifier=str(uuid.uuid4()),
+        unique_identifier=json_driver.unique_cog_identifier,
         driver=json_driver)
     yield conf
     conf._defaults = {}
@@ -59,10 +59,9 @@ def config_fr(json_driver):
     """
     Mocked config object with force_register enabled.
     """
-    import uuid
     conf = Config(
         cog_name="PyTest",
-        unique_identifier=str(uuid.uuid4()),
+        unique_identifier=json_driver.unique_cog_identifier,
         driver=json_driver,
         force_registration=True
     )
diff --git a/tests/core/test_config.py b/tests/core/test_config.py
index 37b6179c5..bf877ec35 100644
--- a/tests/core/test_config.py
+++ b/tests/core/test_config.py
@@ -298,6 +298,16 @@ async def test_member_clear_all(config, member_factory):
     assert len(await config.all_members()) == 0
 
 
+@pytest.mark.asyncio
+async def test_clear_all(config):
+    await config.foo.set(True)
+    assert await config.foo() is True
+
+    await config.clear_all()
+    with pytest.raises(KeyError):
+        await config.get_raw('foo')
+
+
 @pytest.mark.asyncio
 async def test_clear_value(config):
     await config.foo.set(True)