Rennala Queen of the Full Moon

Blue spells you cast cost {1} less to cast.
Instant and sorcery spells you cast have Storm.
Whenever you cast or copy an instant or sorcery spell, if that spell's converted mana cost is four or greater, roll a d20.
1-9: Create a 1/1 blue Wolf Spirit creature token.
10-19: Create a 3/3 blue Troll creature token.
20: Create an 8/8 blue Dragon creature token with flying.