Gollum VS. R2D2 No Rules!!! No Holds Barred!!!
I think R2 would probably beat Gollum just because Gollum is from Middle Earth whereas R2D2 is from a long time ago in a galaxy far, far away where droids are very advanced and carry weapons unfamiliar to Middle Earth. If R2 had to go to Mordor, he'd be like, "been there done that." But only it would sound like, "beep beep boop bip wooOooOOo."