Well I wouldn't think it possible, but you somehow made a bomb cute. There may be no limit to your cute-powers.
I'm not sure if it was the more rural dialect of English, or just a quirk of his own speech, but I almost never heard my grandfather say the word "heart," no, that thing ticking along inside him was always his ticker. Come to think of it, it may have been a dark joke about his ill health and looming moribundity... anyway, I think it's a cute way to say it, morbid as it may seem, and especially given its purpose, I think it's fitting that your cute little C4 explosive has a tiny ticker of its own. ^_^
Maybe the bomb of the cute is only exploding in laughter...
Aww, thank you for sharing the story about your grandfather and his ticker, guess we were thinking on the same wave about the heart being that :)