Or does an arrow fly in the water??  Or is it a harpoon? Or an ‘arpoon?

The sound made by said ‘arpoon as it hits the breathing tank of supposed villain?  TOONK… we certainly can’t have it impaling the poor fellow…  no blood here kids!  Just massively inconveniencing and frustrating the bad guys- that’s what Mark has always been good at…  at least they know how to breathe…