diff --git a/src/init.js b/src/init.js
index 85e4b643f..883aca0ad 100644
--- a/src/init.js
+++ b/src/init.js
@@ -36,3 +36,25 @@ const Raven = require('raven-js');
 
     window._locale = updateLocale();
 })();
+
+/**
+ * -----------------------------------------------------------------------------
+ * Console warning
+ * -----------------------------------------------------------------------------
+ */
+(() => {
+    window.onload = function () {
+        /* eslint-disable no-console */
+        console.log('%cStop!', 'color: #F00; font-size: 30px; -webkit-text-stroke: 1px black; font-weight:bold');
+        console.log(
+            'This is part of your browser intended for developers. ' +
+            'If someone told you to copy-and-paste something here, ' +
+            'don\'t do it! It could allow them to take over your ' +
+            'Scratch account, delete all of your projects, or do many ' +
+            'other harmful things. If you don\'t understand what exactly ' +
+            'you are doing here, you should close this window without doing ' +
+            'anything.'
+        );
+        /* eslint-enable no-console */
+    };
+})();