Fucking fizz...

That is the greatest thing I've ever seen, is there a video of this or something?

alright, i don't know enough about this game so bear with me:

The dude with the staff and Teemo are teammates in this situation, and whereas staff guy coulda withstood that hit maybe, he pops up and lets teemo take the hit?

yes, exactly.
That bullet is the ultimate of a champ called Caitlin. It can be blocked by other teammates. Fizz, the jumper, can become untargetable for .75 seconds, which he did to avoid the shot and let Teemo die.
But hey, it's a teemo. No one can blame the guy.

was there any chance he saw this coming or was that luck? because it seemed pretty damn fast (unsure if gif is sped up)

He saw it coming. The target is there for about 1 second, the shot has to travel then after it is channeled. It will follow the intended target.
Cait's ult is pretty easy to intercept.

Mmkay. And i know Teemo is hated by many, but, if Fizz could have survived the shot, is it better to have two teammates low on heath and regenerating, or to let teemo die and let the enemy feed from that?

Normally, better to have as many people as possible survive. A kill on a champion gives about 300 gold normally. Up to 500 if they are on a killing spree and as low as 150 if they have died multiple times in a row. It's generally not a good idea to give the ADC (attack damage carry) free kills.
So this fizz was just trolling his teammate.
And most of the community would say that the only good Teemo, is a dead one. It's practically a civil service.

not sure if this is 100% true, but I heard that if you die enough times, you will be worth 0 points.

either way, a live teammate is better than a dead correct? Whatever teemos faults may be?

theres no team in teemo

Living teammates are better than dead ones.
It's just funny to kill Teemo.

okay, so im grasping on my minimal LOL knowledge for this next one: There's people who handle lanes, and junglers, and so forth: the shit is teemo supposed to do?

Teemo is a ward.

top lane or bot lane. He's generally an AP (Ability Power) support type character. Players tend to build him with a large amount of attack speed and ability power though. He has a poison that activates with basic attacks that scales damage with his AP.
He also can be very useful seeing as another ability of his blinds the target (all basic attacks miss for the duration of the blind effect), so he can be especially effective against an AD carry.
His ultimate lays a trap for 10 minutes that detonates in a small AOE explosion dealing initial damage and damage over time. Very helpful for getting unsuspecting kills or catching someone or warning the Team of an enemy position as it also gives vision of the effected person for a short time.
His ulti is the main reason he is hated so.

I enjoy playing Teemo mid.

yup. was reading your statement and thinking: "okay.... alright..... mmhmm......... AND THERE IT IS!"

Not considered overpowered at all though?

Not really. He just pisses players off for a couple reasons.
A. Most people who play teemo just suck. They die constantly and feed.
B. Teemo is easy to KS (kill steal) with. Most teemo's will KS a lot.
C. Shrooms (his ulti) are annoying as hell and can deal as much as 1000 magic damage and slow.
D. It's fucking Teemo.
E. Blinding Dart can be OP as it scales well with AP. When against an ADC, watch the health bar drop like a rock.

As a AP Teemo player, I want to address 'A'. Teemo is one of the champs I have highest win rate, but have a weird KD. I often end up carrying a game, but go 7/9, 9/8 or some shit. I have no idea why this is. Teemo is the only champ I have playe where you die a lot, no matter what, but still carry hard. This goes only for pure AP, as far as I've seen. The weirdest part is that I have seen other good players have the same thing happen.

As I said, most players. You are obviously in the some players that are actually good with him. I didn't figure mid lane into my thought process. Mainly bottom lane or top lane, though mostly bot lane ADC or support.

In the higher ranks, Teemo shouldn't be played bot. The amazing 550 range makes him a worthless adc, and he can't support for shit. Hybrid or pure AP are the only viable builds. AP being way more fun.

aaaaalrighty then! I've never been one for playing it but i enjoy spectating and i've never caught on to his annoyingness till now. Anything i can offer in exchange for information? backgrounds or such?

Nah. As a player I'm just keeping those who want to know informed.
Though I don't play the fuzzy little bastard anymore, he's actually a really good pick in a lot of games.

in all fairness, it is teemo.