Some Basic Shaco Math
So, you wanna know how much damage Shaco does? I was bored enough to break his most frequent build (which also has the higher winrate) down to you guys!
Here it goes!
TL;DR: If you're squishy and is not getting at 100 MR and building at least some extra 200 HP, you'll get 100-0'ed in about 0.5 seconds
Considering level 18 for all that matters. Also adjusting for his post-nerf state. Only mastery considered is the Keystone, so that potential +17,5% extra damage won't be taken into account.
>Not related to the maths, but isn't it ridiculous that we can get almost 18% bonus damage from masteries alone? Anyway, back to what you came for! Maths for you nerdz!
BUILD:

KEYSTONE: THUNDERLORDS DECREE
STATS: 567 AP 157 AD 35% MAGIC PEN 15 FLAT MPEN
MATH:
Q: (157 AD + 80 Base Damage + 40% AP Scaling)*1,45
672,5 Damage
: 87,75 Base Damage from his AD + 50% AP Scaling
371,25 Damage
60 Base Damage + 10% AP Scaling
116,7 Damage
250 Base Damage + 30% AP Scaling
420,1 Damage
Thunderlords: 180 Base Damage + 30% Bonus AD + 10% Bonus AP 248,7 Damage
The Auto Attack made out of stealth with a Backstab bonus and a Gunblade Active will deal 1829,25 Damage in about 0.3 seconds as Gunblade has no cast time and the proc from Runic Echoes will trigger Thunderlords.
Seeing as the Average ADC has about 50 Extra Magic resist in his build, he will end up with a total of 80 MR.
This 80 MR will be effectively reduced to 52 due to Void Staff, and then reduced to 37 with Sorc Shoes.
So this combo will get it's damage reduced by 27% and will deal 1335.35 Damage.
Now we get to
's E.
E: 125 Base Damage + 75% AD + 75% AP + 8% of target's missing health So it will deal 125+117.75+425.25+106.8 = 774.8 Damage
This will once again get reduced by 27%, resulting in 565,6 Damage.
The Q+E combo will then result in 1900 TRUE DAMAGE to it's target.
Seeing as ADCs average at 1917 hp, it's fair enough to say that in a team fight, Shaco is more than able to one shot them, specially if we include the %Damage Increase masteries that can add up to an aditional 17,5% extra damage.
Pre-nerf, he'd have an extra 10% AP ratio on his Q (which would become an extra 14,5% with his passive) and an extra 15% AP + 10% AD ratio on his E. This would grant him an extra 190 Damage before reductions or 140 Damage after reductions, meaning his burst used be be at 2050 True Damage, much more than enough to kill a squishy.
thing that every support worth their salt uses around objectives and choke points?
so any retard stumbling across them disables them too
, an item MEANT to fuck with AP assassins, and still be 100-0'ed. At least now the Shaco player needs to be a bit more aware and work around the item's CD or go for hurt targets.