XX-10 was the first of the four "XX-Variant" entities and was added in the April Fools 2023 Event along with other April Fools 2023 Event entities and other changes. It was a runner-type entity that would automatically replace X-10 whenever it should've spawned and had triple its speed. The entity would, just like any runner-types and X-10, spawn from the lobby and rapidly make its way towards the final room before despairing upon contact with the last unopened door. Just like any X-Variant (exc