Pretty sure anyone who played at Diamond V last season knows who this is, but obviously not allowed to name them. Their main account is banned for doing this, so whether or not what they're doing is actually considered intentionally feeding isn't up for discussion.
If you're not sure what you're looking at, it's a Diamond Alistar player who only builds movement speed items and only roams, and still maintains 51-52% win rate. He leaves the ADC to 1v2 and chain ganks top and mid, which gets them snowballing. This works very well, because Alistar has insane early survivability and damage, which lets him make dives.
That part is fine. The part that isn't fine is that as the mid to late game hits, he continues roaming and diving for any champion that gets near him. At this point, he doesn't have the damage or survivability to successfully dive like he could in the early game, and he'll dive **anyone** who gets near him, even if he has no allies nearby. It basically turns into intentional feeding. He builds a ton of movement speed items, so even if someone is near him when he dives, they can't keep up with him during it, and he ends up alone deep in the enemy's base.
Once the late game hits, he just flat out starts intentional feeding, not even something that could pass as 'lol good try' like the mid game dives. If you find any of his games and look at the kill maps, he dies on average once every 60-90 seconds after 25 minutes; he just immediately runs into the enemy team upon respawning.
The fact that he maintains 51%+ win rate while intentionally feeding during the entire mid and late game shows a serious problem with snowballing. **The number advantage his early ganks provide give the solo lanes such a major advantage that his team mates can actually carry him while he's running it down mid lane.**
Also, as a side note, this only actually works because his opponents don't expect it. If you've played with or against him and know he's going to do this, it doesn't work, and he often just ends up with incredibly bad scores like 0-20-6.
This is ridiculous, and I honestly can't see how the first 10 minutes of the game being allowed to have such a huge influence over the outcome is healthy.