The Caterpillar P-5000 Powered Work Loader (AKA, Power Loader), from the classic film, Aliens , was an impressive little Mech built for the simple of purpose of being a fancy pants forklift with legs. It has no life support, weapons, jets, HUD, or pasta-maker attachments (at least none that I saw). However, it handily out-fight the alien Queen in this epic fight scene (Warning, a touch of cursing in this video).
Now with that said a Japanese company has developed (or rather, is developing) a similar Mech, or something close to it. Below is a video they posted on YouTube which goes over its basics. If we can paint it yellow, get Sigourney Weaver to strap it on, and toss a Xenomorph into the mix, we’ll have a real life recreation of that fight scene!