I don't specificaly believe in UFO's and by that I assume you mean Aliens inside the boundaries of earth? But I do believe that there are other life forms in the universe, it would be ignorant to suggest otherwise. But for them to go inside our athmosphere and steal our cows, draw wacky stuff on our cornfields and drain our resources? Highly unlikely, first of all, they don't need our cows, why would they need them? food? when they obviously would have rations with them because it's you know, a space travel operation? And draining our resources seem highly unlikely as well, what would they need our resources when they have been traveling through the universe? Some serious technical stuff is required to do that.
There are inter-dimensional beings (spirit beings, etc.), but there are no aliens from other planets or galaxies. That shit is all Hollywood propaganda. There is no evidence that the "outer space" they have told us about is real. NONE.
The only reason anyone thinks that the universe is such an infinite space with one septillion (1,000,000,000,000,000,000,000,000) other "planets" besides earth is because someone told you. There is no proof. NASA are lying, luciferian freemasons. They have no interest in telling you the truth about anything. Why should they? They want to control you. If you want to control someone, you work at controlling their mind and their thinking. If they feed you nothing but bullshit and lies, then you are absolutely clueless and mentally inept. The dumber people are, the easier they are to control and manipulate.
There is no such thing as space travel. We've been scammed. Do your own research. And have a great day!
https://www.youtube.com/results?search_query=aliens+are+fake