Identify the heaviest superhero in DC Comics.
heaviest refers to MAX(weight_kg); DC Comics refers to publisher_name = 'DC Comics'; superhero refers to superhero_name;
SELECT T1.superhero_name FROM superhero AS T1 INNER JOIN publisher AS T2 ON T1.publisher_id = T2.id WHERE T2.publisher_name = 'DC Comics' ORDER BY T1.weight_kg DESC LIMIT 1