It should be a snake, only with little flashing LEDs in its eyes.

The canonical basilisk paralyzes you if you look at it. Flickering lights carry the danger of triggering photosensitive epilepsy, and thus are sort of real-life basilisks. Even if the epilepsy reference is lost on many, it's still clearly a giant snake thing with weird eyes and importantly you can probably get from somewhere without having to custom make them.

(AFAIK Little LEDs should be too small to actually represent a threat to epileptics, and it shouldn't be any worse than any of the other flickering lights.)

EDIT: Eh, I suppose it could also be stuffed with paperclips or something, if we want to pack as many memes in as possible.