Shares of Google parent Alphabet tumbled Wednesday after its key partner Apple indicated Google’s days of search engine dominance on Apple devices may be numbered, causing Google stock to limp toward one of its largest losses ever,

Alphabet stock sank after senior Apple executive signaled that the iPhone maker was looking at search engine alternatives for its Safari web browser.

Shares of Alphabet ( GOOGL -1.02%) ( GOOG -0.92%) sank after Apple executive Eddy Cue said that searches on Safari declined for the first time ever in April. Cue attributed the decline to people using more artificial intelligence (AI) chatbots and predicted that AI search engines will eventually replace traditional search.