Nuclear bomb rock

The Nuclear Bomb-Rock was originally created for Pikmin: Sinister Incinerator, but it has been seen in other non-canon games as well since then. It's a special type of bomb-rock which has a slightly green interior, which can be seen through very small cracks on the outside of the rock. If it takes damage, its energy gauge will deplete at a very slow rate, taking approximately 128 seconds to reach the end. At that point, it will instantly explode, completely destroying the entire sublevel and everything in it- so you should take care to not set these off. Sometimes, it's unavoidable, though... so if it happens to get hit, finish up whatever you're doing fast and move on to the next floor. If you're at the end of your wits end with no way out, just give up and escape. Plan better for next time!

Portal- Kombat  *Sysop*

In Pikmin: Connection of the Worlds
The Nuclear Bomb-Rock also make an appearance in Pikmin: Connection of the Worlds. In the tougher caves, later on in the game, there is a rare chance that a Nuclear Bomb-Rock will appear in any of these caves. It will be dormant when it falls, but even the tiniest touch will activate it. Should that happen, a geyser will randomly appear somewhere in the sublevel. It only has 120 seconds until it finally explodes, not just taking the sublevel with it, but the entire cave. So drop what you're doing, and find that geyser and open it up, so you can get out of there! When you land outside, rumbling will be felt. The cave you just exited will suddenly shoot out a green gas. It will then explode, creating a huge crater, and sending a shockwave throughout the area. It turns out that it's a radioactive shockwave, which can kill any Pikmin if not treated. The day immediately ends and you blast off into the atmosphere, watching the area below fall into ruins. You can return to the area in 5 days. The hole will come back in 20 days. So be excruciatingly careful when you encounter a Nuclear Bomb-Rock!