diff --git a/Library/Homebrew/cask/utils.rb b/Library/Homebrew/cask/utils.rb
index 23e52b91c8a37..e47510ca3c234 100644
--- a/Library/Homebrew/cask/utils.rb
+++ b/Library/Homebrew/cask/utils.rb
@@ -104,7 +104,7 @@ def self.method_missing_message(method, token, section = nil)
       message << "during #{section} " if section
       message << "on Cask #{token}."
 
-      opoo "#{message}\n#{error_message_with_suggestions}"
+      ofail "#{message}\n#{error_message_with_suggestions}"
     end
   end
 end
diff --git a/Library/Homebrew/test/cask/dsl_spec.rb b/Library/Homebrew/test/cask/dsl_spec.rb
index 106770a4f5ed5..61eadc8fea69e 100644
--- a/Library/Homebrew/test/cask/dsl_spec.rb
+++ b/Library/Homebrew/test/cask/dsl_spec.rb
@@ -20,10 +20,10 @@
       end
     end
 
-    it "prints a warning that it has encountered an unexpected method" do
+    it "prints an error that it has encountered an unexpected method" do
       expected = Regexp.compile(<<~EOS.lines.map(&:chomp).join)
         (?m)
-        Warning:
+        Error:
         .*
         Unexpected method 'future_feature' called on Cask unexpected-method-cask\\.
         .*