diff --git a/README.md b/README.md
index bd56ebb..4497e79 100644
--- a/README.md
+++ b/README.md
@@ -679,7 +679,7 @@ def func(<default_args>): ...                     # def func(x=0, y=0): ...
 def func(<nondefault_args>, <default_args>): ...  # def func(x, y=0): ...
 ```
 * **Default values are evaluated when function is first encountered in the scope.**
-* **Any mutation of a mutable default value will persist between invocations.**
+* **Any mutation of a mutable default value will persist between invocations!**
 
 
 Splat Operator
diff --git a/index.html b/index.html
index 3d72401..a277b5a 100644
--- a/index.html
+++ b/index.html
@@ -601,7 +601,7 @@ func(&lt;positional_args&gt;, &lt;keyword_args&gt;)           <span class="hljs-
 
 <ul>
 <li><strong>Default values are evaluated when function is first encountered in the scope.</strong></li>
-<li><strong>Any mutation of a mutable default value will persist between invocations.</strong></li>
+<li><strong>Any mutation of a mutable default value will persist between invocations!</strong></li>
 </ul>
 <div><h2 id="splatoperator"><a href="#splatoperator" name="splatoperator">#</a>Splat Operator</h2><div><h3 id="insidefunctioncall-1">Inside Function Call</h3><p><strong>Splat expands a collection into positional arguments, while splatty-splat expands a dictionary into keyword arguments.</strong></p><pre><code class="python language-python hljs">args   = (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>)
 kwargs = {<span class="hljs-string">'x'</span>: <span class="hljs-number">3</span>, <span class="hljs-string">'y'</span>: <span class="hljs-number">4</span>, <span class="hljs-string">'z'</span>: <span class="hljs-number">5</span>}