Nightmare King Grimm

Indestructible, hexproof, infect, Haste, Trample, doublestrike, firststrike.
Pay 10 life add 10{r}
When nightmare king grimm attacks
Create x tapped and attacking 2/2 phantom tokens with flying where x
Is the total life players lost this turn.
If you kill a player you gain infinite red mana until your next end step