"Angry Grandpa" was the alias of Charles Green, a YouTube celebrity who makes videos of himself going into destructive rages over little things.
Despite being a very popular YouTuber, he had many videos go missing over the years, which have no mirror upload whatsoever. One such instance is, "the bomb prank", a presumably early prank from around 2011. It was removed for legal reasons and because of negative backlash. Another famous missing video was the sequel to "the heart attack prank", a presumably revised version of the original. It was also removed due to negative reception from fans (of which Charles cared about quite a bit).
Yet another video was of Michael singing The Andy Griffith Show theme song very shrilly. This video was made shortly after Andy Griffith's death, and it was likely removed out of respect. In addition to these, a handful of other videos have also been removed for various reasons.
The only evidence of the infamous "bomb prank" is a screen capture of the video, showing the old kitchen. Chances of anyone having made a copy of the video is very unlikely since the channel was a relatively little-known one back then.