What do scientists believe happened to Uranus?

They believe that Uranus some how got tipped over by something, so now it spins weird. I disagree though. Since Uranus is a gas planet then how could it be tipped over on to its side? It would just go through it, right? But then comes the question of how could it go through it cause of its high winds? Well the "something" would just take anouther course, right? Some of these question i guess we'll never know.