I'll try to explain it a little further in detail
Start of the fight:
1. iG smokes to become invisible to enemy wards' vision while flanking Navi
2. Dark Seer puts surge on Naga so she can move into position while Naga uses Song of the Siren to sleep the enemy team (they cannot move or take damage).
3. DS Vacuums 4 of Navi's players into a single spot during Sleep (vacuum has later been patched to no longer move slept heroes).
Here's what key heroes do as the sleep ends and Navi regains control of their heroes:
Naga:
1. Activates illusions in preparation to do a bunch of damage.
2. Uses Riptide to nuke and reduce enemy armor in AOE.
Tide:
1. Is still running into position as sleep ends, presumably to try to catch Juggernaut (who is further away and was not vacuumed by DS) with Ravage as well.
2. Ravage used, only affects 2/5 Navi heroes.
3. The delay between Sleep ending and Ravage activating allowed Juggernaut to Bladefury, Rubick to Force Staff, and Enigma to BKB, nullifying any Ravage effects to them.
4. After Ravage, Tide tries to Anchor Smash to do damage AND "cover up" his ravage spell so that it cannot be stolen by Rubick.
5. Near the very end of his Anchor Smash animation, Enigma uses Black Hole to prevent Anchor Smash from activating, leaving Ravage as the last spell used.
6. Ravage gets stolen by Rubick.
Rest of iG:
1. Puck throws nuke and jumps into middle of the fight to nuke some more. Gets Blackholed as he jumps in.
2. Lina Throws nuke. Gets Lifted by Rubick. Then hit by Ravage.
What Navi does as song ends:
Enigma:
1. Mashes BKB to activate as quickly as possible.
2. BKB means Ravage does nothing to him
3. Hits the Black hole on 4 iG heroes grouped next to him
Rubick:
1. Mashes Force Staff to leap away from Tide who is about to Ravage
2a. Activates Haste Rune he has stored in his bottle to give him max movement speed.
2. Lifts Lina to disable her
3. Turns around and steals Ravage
4. Ravages all 5 iG heroes
5. Throws nuke to finish off some iG heroes
6. Chases sown Lina to finish the team wipe
Juggernaut:
1. Mashes Bladefury which grants magic immunity (e.g. from ravage)
2. Bladefurys the iG heroes being Black Holed.
Enchantress:
1. Activates Nature's Attendants which heals over time in an AOE
2. Gets hit by Ravage
3. Pops Mekansm (an instant AOE Heal)
Shadow Shaman:
1. Gets hit by Ravage
2. Nukes enemy team
3. Sheeps someone
Most of this stuff after the song ends happens in about 5 seconds of real time, it's pretty unreal.