diff --git a/contrib/spoiler/main.php b/contrib/spoiler/main.php
new file mode 100644
index 00000000..9fb8c31d
--- /dev/null
+++ b/contrib/spoiler/main.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * Name: Spoiler Filter
+ * Author: Shish <webmaster@shishnet.org>
+ * Link: http://trac.shishnet.org/shimmie2/
+ * License: GPLv2
+ * Description: Adds a [spoiler] tag to rot13 text inside it
+ */
+class Spoiler extends Extension {
+	public function receive_event($event) {
+		if(is_a($event, 'TextFormattingEvent')) {
+			$event->formatted = $this->filter($event->formatted);
+			$event->stripped  = $this->filter($event->stripped);
+		}
+	}
+	
+	private function filter($text) {
+		$l1 = strlen("[spoiler]");
+		$l2 = strlen("[/spoiler]");
+		while(true) {
+			$start = strpos($text, "[spoiler]");
+			if($start === false) break;
+			
+			$end = strpos($text, "[/spoiler]");
+			if($end === false) break;
+
+			$beginning = substr($text, 0, $start);
+			$middle = str_rot13(substr($text, $start+$l1, ($end-$start-$l1)));
+			$ending = substr($text, $end + $l2, (strlen($text)-$end+$l2));
+
+			$text = $beginning . $middle . $ending;
+		}
+		return $text;
+	}
+}
+add_event_listener(new Spoiler(), 45); // before bbcode, so before <br>s are inserted
+?>