Suppaman! (Sourman) Dr. Slump’s Antihero

Suppaman, called Sourman (すっぱい suppai = sour, he eats umeboshi pickled plums) is a superhero-wannabe. “Suppaman” sounds similar to the Japanese pronunciation of Superman, Suupaaman (スーパーマン)
The Japanese Hiragana on his chest す translates to Su, which means “Sour”.