Since it's tethered to Kirby and arcs over him in a devastating sweep, the electro-charged boulder has incredible range.”
— Description • Official Strategy guide
Lightning Boulder is a combo ability from Kirby 64: The Crystal Shards. When Kirby combines Stone with Spark, he gets this ability. It is one of Kirby's more abstract abilities; he spits out a rock, connected by electricity from his body (as if it were a flail). He can still move while he is using it, but cannot float. The rock will bounce off of walls but the electric wire can go through them.
Kirby shoots out a giant rock, connected to Kirby by electricity. The rock will bounce around and damage anything it touches. When B is pressed or if the rock hits Kirby, it will explode. Kirby cannot float while this attack is being used.
Kirby slings a big boulder around with an electrically charged tether.”