The spores of the Blastcap can survive in outer space, and have propagated throughout the galaxy by means of traveling on interstellar solar winds. When approached, they will make a rustling noise and shake violently. Upon contact with Samus or when sufficiently damaged, they will explode, destroying them. The explosion will damage Samus as well as release a cloud of gas. Contrary to its scan data, the gas is not harmful.
Blastcaps are also encountered in Metroid Prime Hunters on both Alinos and Arcterra. The type that appears on Arcterra seems to be a white arctic species, though they appear to be merely scenery and can not be scanned.
"Volatile chemicals within this weed's toxic fungal cap may explode if agitated. The poisonous flesh of the Blastcap helps keep it from being eaten. It also detonates its fungal cap when it senses even slight contact."
Metroid Prime Hunters
"A large mushroom that explodes on contact, emitting noxious gas. Originating on TALLON IV, its spores can survive without atmosphere and have propagated throughout the galaxy on solar winds."