Bomb Sniffer
From Inkipedia, the Splatoon wiki
Bomb Sniffer is an ability that allows you to easily spot opponents' Ink Mines and Bombs. All bombs within a certain distance appear as skull icons on your screen. These skull icons can be seen through walls. This Ability is restricted to shoes as a main ability.
In-Depth Ability
Use
Bomb Sniffer is used to track down nearby Ink Mines and Bombs that have been placed by the enemy. This does not activate or expire and is a permanent ability that can last the whole match. Ink Mines and Bombs are marked as skulls as mentioned before and can be shot down or avoided to allow safer passage through the map. This ability is especially useful for spotting Seekers.
Gear
Bomb Sniffer is the main ability of: