Oracle Text

Rile deals 1 damage to target creature you control. That creature gains trample until end of turn.

Draw a card.

Card Rulings

9/29/2017 If Rile targets a creature with 1 toughness, that creature won’t be destroyed until after you’ve drawn a card. Its abilities may affect that draw or trigger on that draw if appropriate.
9/29/2017 If the damage that would be dealt by Rile is prevented, the creature still gains trample until end of turn.
9/29/2017 If the target creature is an illegal target by the time Rile resolves, the entire spell doesn’t resolve. You won’t draw a card.