His permanent elastic powers manifest after the S.T.A.R. Labs team open up the Speed Force to free Barry, which opens a breach in front of a city bus Ralph was riding on, exposing it to dark matter, transforming the passengers into metahumans.
After the S.T.A.R. Labs team open up the Speed Force to free Barry exposing it to dark matter, transforming the passengers into metahumans. This is what his permanent elastic powers manifest. Barry opens a breach in front of a city bus. Ralph was riding on a breach in front of a city bus.