Octoballer
From Inkipedia, the Splatoon wiki
Octobowers are Octarians in Splatoon 2 Octobowlers are fired from canons and will roll on the ground, killing anything that gets in the way. They can be destroyed by attacking the tentacle. Some Octobowlers will not leave behind a trail of ink. The giant Octobowlers move slower, but they can only be destroyed with ink canons