Los Angeles, April 1 : Filmmaker Michael Bay recently shared that he should've stopped making the 'Transformers' films at a certain point. According to 'Variety', he told Unilad UK (via IndieWire). Bay directed 2007's 'Transformers', which grossed $709 million worldwide, and then returned for four sequels. Two follow-up films, 'Transformers: Dark of the Moon' and 'Transformers: Age of Extinction', grossed over $1 billion worldwide. According to Bay, even franchise executive producer Steven Spielberg told him to stop after the third movie, reports 'Variety'. "I made too many of them," Bay said. "Steven Spielberg said, 'Just stop at three'. And I said I'd stop. The studio begged me to do a fourth, and then that made a billion too. And then I said I'm gonna stop here. And they begged me again. I should have stopped. (But) they were fun to do." Bay's final 'Transformers' outing, the Mark Wahlberg-starring 2017 entry 'Transformers: The Last Knight', bombed with film critics and grossed a franchise low $605 million worldwide. Bay told Unilad UK that he still remembers just how "scary" it was taking on the original 'Transformers' movie. "It was technology we didn't know would work, and then it became very successful," Bay said. "It was the first time digital effects were that highly reflective, so it broke a lot of new ground. It was a fun experience. It made more than ($709 million), that's a lot of movie tickets and a lot of people that have seen it." Bay stepped away from directorial duties on the aTransformers' franchise starting with the 2018 spinoff movie 'Bumblebee', which was directed by 'Kubo and the Two Strings' animation director Travis Knight in his live-action debut. The 'Transformers' franchise is returning in 2023 with 'Transformers: Rise of the Beast'. Set in the year 1994, the upcoming tentpole is directed by 'Creed II' helmer Stephen Cable Jr. and stars Anthony Ramos, Dominique Fishback and Luna Lauren Velez. Bay's next is titled 'Ambulance', an action thriller, which will release on April 8. /IANS