diff --git a/bot.py b/bot.py
index adab7bf..5f3f88f 100755
--- a/bot.py
+++ b/bot.py
@@ -106,6 +106,9 @@ class Fulvia(irc.IRCClient):
 		the URL module.
 		"""
 
+		self._user_joined = []
+		"""These get called when a user joins a channel."""
+
 		self._disabled_modules = self.config.core.disabled_modules.split(",")
 		"""These modules will NOT be loaded when load_modules() is called."""
 
@@ -171,6 +174,9 @@ class Fulvia(irc.IRCClient):
 			for url in func.url_callback:
 				self.url_callbacks[url] = func
 
+		if func.user_joined:
+			self._user_joined.append(func)
+
 
 	def unregister_callable(self, func):
 		"""
@@ -196,6 +202,9 @@ class Fulvia(irc.IRCClient):
 			for url in func.url_callback:
 				self.url_callbacks.pop(url)
 
+		if func.user_joined:
+			self._user_joined.remove(func)
+
 
 	def stillConnected(self):
 		"""Returns true if the bot is still connected to the server."""
@@ -364,6 +373,8 @@ class Fulvia(irc.IRCClient):
 
 	def signedOn(self):
 		"""Called when the bot successfully connects to the server."""
+		if self.config.core.oper_password:
+			self.sendLine("OPER " + self.config.core.nickname + ' ' + self.config.core.oper_password)
 		print(f"Signed on as {self.nickname}")
 		self.whois(self.nickname)
 
@@ -412,6 +423,12 @@ class Fulvia(irc.IRCClient):
 			self.users[nick] = tools.User(nick)
 		self.channels[channel].add_user(self.users[nick])
 
+		for func in self._user_joined:
+			trigger = Trigger(user, channel, f"{user} has joined", "PRIVMSG", self.config)
+			bot = FulviaWrapper(self, trigger)
+			t = threading.Thread(target=self.call,args=(func, bot, trigger))
+			t.start()
+
 
 	def userLeft(self, user, channel, reason=""):
 		"""Called when the bot sees another user leave a channel."""
diff --git a/loader.py b/loader.py
index c57f52c..80ca9b9 100755
--- a/loader.py
+++ b/loader.py
@@ -67,7 +67,7 @@ def is_triggerable(obj):
 	Checks if the given function object is triggerable by Fulvia, eg. has
 	any of a few particular attributes or declarators defined.
 	"""
-	triggerable_attributes = ("commands", "hook", "url_callback")
+	triggerable_attributes = ("commands", "hook", "url_callback", "user_joined")
 	return any(hasattr(obj, attr) for attr in triggerable_attributes)
 
 
@@ -92,6 +92,7 @@ def process_callable(func, config):
 	func.channel_rate = getattr(func, "channel_rate", 0)
 	func.global_rate = getattr(func, "global_rate", 0)
 	func.priv = getattr(func, "priv", 0)
+	func.user_joined = getattr(func, "user_joined", False)
 
 	if hasattr(func, 'commands'):
 		if len(func.commands) > 1:
diff --git a/module.py b/module.py
index fa2bbbc..94246a5 100755
--- a/module.py
+++ b/module.py
@@ -249,4 +249,19 @@ def url_callback(url):
 		function.url_callback.append(url)
 		return function
 	return add_attribute
-	
\ No newline at end of file
+
+
+def user_joined(value=False):
+	"""
+	Decorate a function to be called every time the bot sees a user join.
+
+	Args:
+		value: Either True or False. If True the function is called every
+			time a PRIVMSG is received. If False it is not. Default is False.
+
+	Note: Do not use this with the commands decorator.
+	"""
+	def add_attribute(function):
+		function.user_joined = value
+		return function
+	return add_attribute
diff --git a/modules/adalwulf__.py b/modules/adalwulf__.py
new file mode 100644
index 0000000..5311a08
--- /dev/null
+++ b/modules/adalwulf__.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""
+Renames defaultnick's to Adalwulf__.
+"""
+from module import user_joined, commands, require_owner
+
+MAX_NICKLEN = 100
+NICK_ZERO = 'Adalwulf_'
+
+def new_bot_name(number):
+	"""
+	Accepts the number of the new bot. Returns the nickname.
+	"""
+	max_underscore = MAX_NICKLEN - len(NICK_ZERO)
+	pluses = 0
+	while number > max_underscore * 2:
+		pluses += 1
+		number -= max_underscore * 2 + 1
+		max_underscore -= 1
+	equals = max(number - max_underscore, 0)
+	under = min(number, max_underscore) - equals
+	nick = NICK_ZERO + '+' * pluses + '|' * equals + '_' * under
+	return nick
+
+
+@user_joined(True)
+def adalwulf_(bot, trigger):
+	"""Renames adalwulf__."""
+	print(True)
+	print(trigger.nick)
+	if not trigger.nick.startswith('defaultnick'):
+		return
+	names = bot.channels[trigger.channel].users
+	adals = [nick for nick in names if nick.startswith('Adalwulf__')]
+	adals += [nick for nick in names if nick.startswith('Adalwulf_|')]
+	old_nick = trigger.nick
+	new_nick = new_bot_name(len(adals) + 1)
+	bot.sendLine(f"SANICK {old_nick} {new_nick}")
+
+
+@require_owner
+@commands('rename_hydra')
+def rename_hydra(bot, trigger):
+	"""Renames defaultnick's appropriately."""
+	for nick in list(bot.channels[trigger.channel].users.keys()):
+		if not nick.startswith('defaultnick'):
+			continue
+		names = bot.channels[trigger.channel].users
+		adals = [nick for nick in names if nick.startswith('Adalwulf__')]
+		adals += [nick for nick in names if nick.startswith('Adalwulf_|')]
+		old_nick = nick
+		new_nick = new_bot_name(len(adals) + 1)
+		print(f"SANICK {old_nick} {new_nick}")
+		bot.sendLine(f"SANICK {old_nick} {new_nick}")