shift+p to activate

rotatopotato.user.js

// ==UserScript==
// @name        Rotato Potato
// @namespace   zerf
// @description Yep
// @include     *
// @version     1.3
// @downloadURL https://gist.github.com/zerfgog/3695d12eac2061f6e29930d7c4fb91ff/raw/master/rotatopotato.user.js
// @require     https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js
// ==/UserScript==

var scriptString = "\
<style>\
html {\
	-webit-animation: rotatopotato 4s alternate infinite;\
	animation: rotatopotato 4s alternate infinite;\
}\
\
@keyframes rotatopotato {\
	from { transform: rotate(-45deg); }\
	to { transform: rotate(45deg); }\
}\
\
@-webkit-keyframes rotatopotato {\
	from { transform: rotate(-45deg); }\
	to { transform: rotate(45deg); }\
}\
</style>\
"
var $script

$(document).keypress(function(e) {
	if (e.shiftKey && e.which == 80) {
		if ($script && $script.length) {
			$script.remove();
			$script = null
		} else {
			$script = $(scriptString).appendTo("head");
		}
	}
});