They made an idol of a calf at Sinai and bowed to worship their man-made statue.
“So they made a god, an idol in the form of a bull calf. They offered sacrifices to it and celebrated with delight what their own hands had made.
and practicing idolatry, as some of them did. For it is written: The people settled in to their unrestrained revelry, with feasting and drinking, then they rose up and became wildly out of control!