User blog comment:TheNewBuildGuy/Possibilities-- Jungle Zyra/@comment-99.187.230.227-20130228065816/@comment-6301771-20130228214617

Thresh gains bonus damage on hit for each soul he collects. This isn't effected by how long he builds up his swing, but EVERY HIT. He scales infinitely into late-game and, while everyone keeps going "Oh his range is too low!" they forget 2 very important things.

1. Armor per soul.

2. His kit. Namely his grab, which gets him within range, and his ult which keep them within range.

Thresh has outrageous utility and building attack damage turns him into a nuking king, capable of shredding the faces of anyone dumb enough to try and engage the "Squishy AD carry." He's NATURALLY tanky, NATURALLY has damage, and NATURALLY has utility: Augmenting all of that with as much gold as he can get turns him from a potent support to a carry so powerful he can solo Baron at the 30 minute mark without a second thought.