Roshan drops an aegis that gives the hero an extra life every time he dies (only lasts 6 minutes in inventory, but Roshan won't respawn for 10 minutes after he's killed.) Starting with the third time Roshan is killed and every time after that, he also drops Cheese, which heals +1500 HP/+1500 MP on use, or can be sold for (I think) 500 gold.
Highlight of the game was when everyone on both teams were dead, I'm alive with like 300 HP and Alchemist is alive with like 800 and pushing our tier 4 towers with super creeps. I walked up to him with Shadowblade, crit him for 1500 damage, and got killed by the little static shield thingie from his Mjollnir (chance to zap anyone that attacks the target for like 250 damage or something) and both basically died on top of each other.So I shall.
And then everyone sat around for about 10 seconds before people started respawning.