From StrategyWiki, the free strategy guide and walkthrough wiki

Golden monsters are special, stronger versions of some monsters. Sometimes when you fuse kinstones with someone, a golden monster will appear somewhere in Hyrule. The golden monster's location depends on where its symbol is on your map. When defeated, golden monsters leave behind either a giant green or giant red rupee. The three types are golden octorok, golden tektite, and golden rope.

[edit] Octorok

The golden octorok will shoot rocks more aggressively than normal octoroks.

[edit] Tektite

The golden tektite will jump around much faster than normal tektites.

[edit] Rope

The golden rope is much more aggressive than normal ropes.