Grenzo, The Gambler

ETB rolls a D6, power and toughness are
equal to the result.{b}{g}: Roll a D6, OPT.
Whenever you roll a die and the results are:
4: Creatures you control get +4/+4 and Trample UET.
5: Create 2 5/5 Goblins.
6: Take an extra turn.
On your upkeep roll a D20, power and toughness are equal to the result.