From LATimes.com:

Knerr died Monday at Methodist Hospital in Arcadia after suffering a
stroke earlier in the day at his Arcadia home, said his wife, Dorothy.

With his boyhood best friend, Arthur "Spud" Melin, Knerr started the
company in 1948 in Pasadena. They named the enterprise Wham-O for the
sound that their first product, a slingshot, made when it hit its
target.

A
treasure chest of dozens of toys followed that often bore playful
names: Superball, so bouncy it seemed to defy gravity; Slip ‘N Slide
and its giggle-inducing cousin the Water Wiggle; and Silly String,
which was much harder to get out of hair than advertised.

Both Knerr and Melin were SC graduates, so this is somewhat related to this blog.  As an entrepreneur myself, I found the story of how he started his company entertaining.  The obituary is worth reading in its entirety.