"Rock icicle" is a subterranean species on SR388. The only occurrence of an official name of this creature exists in Japanese Metroid II: Return of Samus guides. It appears to crawl out of an orifice in the cavern ceilings, then drops down in an attempt to hit Samus Aran. These odd, fish-like creatures live in caverns that formerly contained SR388's acid. Their attack pattern is similar to that of a Skree in the manner of dropping down from above; however, it does not explode upon contact with the ground. It appears to live in some sort of family group, due to the seemingly infinite number of them that drop from a single spot. Strangely, these creatures stop crawling out of the orifice as soon as Samus kills a single one of them.