In last night's episode of Steven Universe, Steven discovers that Amethyst and Pearl can fuse to form Opal, a form of larger size and power. Steven then spends the rest of the episode trying to get them to form a "giant woman".
He even sings a song about it:
(Cartoon Network posted a short ringtone of it for download:
https://twitter.com/cartoonnetwork/s...83602921054208 )
You see an example of the fusion with sand sculptures and a failed attempt, but the actual completed fusion happens offscreen. However, she sticks around for most of the rest of the episode.
Don't have any screenshots or vids of it so far, but new SU episodes rerun multiple times a week. Should be easy to catch on Friday/Saturday or on the CN site or whatever.