Toilet problem.

This past week, whenever I've been flushing, as soon as the tank starts to refill, two stream of water come running out from under the lid and down the outside of the tank and spill onto the floor. I opened up the top, and discovered that for whatever reason, like half of the spout of water that refills the tank sprays upward onto the lid, and that's what's causing it.

Still haven't notified my landlord, I keep forgetting.