Movement prediction is a display option that only comes into play if you temporarily lose your connection to the game server. Without it, your champion will appear to stand still until you regain connection and receive your true position from the server. With it, your champion will appear to move to the location you last directed it to.
Rammus' great strength comes with the element of surprise. If Rammus isn't in your face, and he isn't powerballing, then he's not scary.
First, the general Powerball gank-tip: start charging it before you actually go in to gank. It takes some time to get spinning, but lasts for quite awhile. If you just press Q and charge on in, you give your opponent precious escape-time. Figuring out the timing on this is critical.
Second, wards. Namely, destroying their's. Rammus late-game can be something like Fiddlesticks; if you can get the jump on them from a surprising position, you've really got something. Have an oracle's on your team (either you or your support) and clear out those wards. Leave them guessing.
Third, scaling MR blues. Rammus needs MR, and these provide a healthy chunk.
Fourth, effective team communication. When Rammus goes in, he goes in. He isn't getting back out. If your team is not prepared to jump in after you, you're going to have a bad time.
Fifth, make use of your early-game advantage. Rammus is FRIGHTENING during the laning phase. If you manage your Powerball correctly, and your lanemate has any CC at all, you're pretty much guaranteed a kill. Gank frequently.
Sixth, give your lanemates the kills, whenever and wherever possible. Don't ever let a kill get away, but if the opponent is certain to drop, give it to your lanemate. They can put that extra gold to much better use.
Best Answer
This is explained only in Zac's wiki page, and nowhere in-game or the client. I find this really annoying because this is kind of important (or at least interesting) stuff to know if you're playing Zac.
Zac has an innate passive that has two effects. First:
Thus, as you gain bonus health via items you buy throughout the game, Zac will get larger. This is capped at 2333.33 bonus health, so if you get more bonus health than that, you will not grow any larger.
The second part of this innate ability reads:
Which means that as you either take damage or damage yourself by using Zac's abilities throughout the game, Zac will get smaller (and his voice will get higher pitched). You'll notice that as you get healed or take damage, Zac's size will continue to vary, as his size updates in real-time as his health pool changes.
Like all other champions, when Zac increases his size, his hitbox radius is larger, and he can be targeted by edge-to-edge targeted abilities and ranged auto-attacks from further away than the center of his hitbox (i.e. he's bigger, you can hit him from further away). When he's at his lowest possible size value when he's at 0% health, his size is 56 units, which is 1 unit larger than very small champions like Annie and Amumu. These size changes do not affect the range of his abilities.