What does Snowballing mean

Aggro as a term originated in MMO's, but its usage has spread considerably.

Originally it was coined to describe any creature who would attack you on sight. So an "aggro" mob was one who would attack without being provoked, as opposed to one who wouldn't attack unless you attacked it first. The related usages here are "aggro range" or "aggro radius" which is the distance at which the mob will attack, and "aggro chain" which is whether or not the mob will bring his friends along, even if they are outside of normal aggro range.

As the games evolved "aggro" became the state of being attacked. If you were being attacked, you "had aggro", and if you did too much damage to something and it started attacking you instead of someone else you "stole aggro". If you did something stupid you could have "too much aggro" which meant too many things were drawn to attack you.

In your example, he's saying that the unit AI can be exploited because they don't chain aggro, so you can move into their aggro range, and individually "pull" them from their groups and eliminate them one at a time.

Proxy Singed is a strategy designed to take advantage of Singed strengths and confuse the enemy team.

The strategy is usually executed as following :

• Singed runs teleport / ghost summoner spells for better escape and ability to come back quickly after dying
• Singed usually starts flask / ward / pots (ward in enemy jungle to teleport after first death)
• Singed will be farming between enemy turrets from level 1, clearing the minion waves with his poison while avoiding most of melee minion damage
• Singed will not care about dying, and will only focus on farming minion waves

The key benefits of the strategy are these :

• By farming enemy minion waves between turrets, the enemy top laner must either tank Singed minions, or let them reach his turret. This will usually make last hitting harder for the enemy laner, denying some gold
• If the enemy top laner tries to chase Singed, he will lose minions, and let them get an easy tower
• After each death, killing Singed will reward less and less gold, whereas Singed will still be denying farm through his proxy farming
• The enemy team will usually send their jungler and / or mid laner help to handle Singed and kill him, meaning Singed team is given free map control, allowing for easy objectives (mid / bot turrets, drake, ...)

This strategy is best run with Singed, because he has great escape capabilities with his ult, poison, and ghost. He can farm minion waves easily with his poison while avoiding most of minion damage. Even if Singed dies a lot, he should still get more than decent farms (he can even go farm top and mid lanes inside enemy base after level 6) and be efficient for end game teamfights.

The biggest disadvantage of this strategy is that Proxy Singed requires a team knowing how to take advantage of the map pressure created by Singed. If your teammates don't get objectives while Singed is being chased, the strategy is a lot less efficient.

There is no real hard counter to the strategy, as the enemy team cannot leave Singed farming freely inside their base, but chasing him will leave objectives open. The best ways to handle a proxy farming Singed are :

• Have a good wave clearing top champion (riven, chogath, zac, zed,). Go proxy farming once you're able to, this will negate the pressure created by singed.
• Ward your top jungle properly and keep it warded. Punish Singed as soon as he tries to enter your jungle.
• Use snowbally champions that will have a higher impact on teamfights than Singed coming to end game
• Invest in mejai or sword of the occult, get free stacks on Singed if he continues his proxy farming

Note that the latest patch have made the proxy farming less efficient, by reducing the death strike penalty on kills, making killing Singed more rewarding in such cases.