Level 1 you see the human version of Warwick.
Level 6: The first time he uses his ultimate he changes to look like the classic "Wolfman" type werewolf. Short snout if any, ripped clothing, claws slightly larger than his human hands and no tail. When he dies he comes back in his human form until dealing damage to a unit.
Level 11: The first time you use your level 2 ultimate you transform from whichever form you are in to a form more like the current Warwich, wolf head, large claws, tail with barely any tattered clothes left. Death again reverts you to your human form until dealing damage.
Level 16: The first time you use your level 3 ultimate the beast is released. Hes larger than his other forms, he runs on all fours when his blood scent detects wounded prey. But not even death can bring his human form back, theres no humanity left in this monster.
Your move Riot.
Shoutout to Hobbsgoblin (NA) for coming up with this idea