Activate Goblin Bombardment by sacrificing River Kelpie.
When River Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to Melira.
When River Kelpie enters, it triggers, causing you to draw a card
Resolve the Goblin Bombardment ability.
Repeat.
This ingenious loop relies on Melira, Sylvok Outcast and her passive ability to completely negate the drawback of persist, allowing River Kelpie to return from the graveyard completely free of -1/-1 counters every time it dies. With that infinite recursion secured, you can repeatedly feed River Kelpie to Goblin Bombardment to deal endless damage to any target. Meanwhile, River Kelpie's own graveyard-entry trigger takes advantage of this constant cycle to draw your entire deck card by card.