If you have a lightning or supercharged creeper, water looks weird, often nearby entities go invisible/translucent, and all kinds of tileEntities and entities glitch out.
1. Pick one (CREATIVE MODE!!): summon a supercharged creeper: {{/summon Creeper ~ ~ ~

}} OR spawn a creeper with an egg and use /summon LightningBolt. This will result in a lightning creeper.
2. Spawn in nearby entities, like other regular creepers, endermen, place water and chest and other tileEntities, and as much randomness as you can.
3. Move around. You will notice the water looks weird through the supercharged/lightning creeper's animation, some of the entities disappear or become partially invisible, and the tileEntities go all glitchy.
4. If you don't see it, it may not happen with your video settings. I'd try adjusting them randomly.

You may have noticed similar things happen with semitransparent jackets on the player, but are much less noticeable, and are separate bugs.