Terror of the Tadpoles

Unlock flying through Battle for Azeroth Pathfinder, Part 1 and Part 2, then obtain Monel-Hardened Stirrups from the Auction House or via Blacksmithing, and optionally pick up Comfortable Rider's Barding from the Auction House or via Leatherworking to prevent daze while mounted. Use the Stirrups before heading out — they last 2 hours and let you click on tadpoles without dismounting.

Head to Bloodfin Village at 31.4, 31.4 in Nazjatar and click on the friendly Bloodfin Tadpoles to shoo them — each click counts as one toward the 100 total. Be aware that every tadpole you shoo spawns 1–2 enemy Bloodfin Sentries in its place, which immediately put you in combat and slow progress if left alive. Progress from tadpoles is not shared in a group, so each player must click their own tadpoles.

If the world quest is active at Bloodfin Village at 31.29, 31.8, take advantage of it — other players killing murlocs for the quest will clear the Bloodfin Sentries that spawn when you shoo tadpoles, letting you move through the area faster and focus entirely on clicking the green tadpoles.

After shooing approximately 25 tadpoles, the rare King Gakula will spawn — his final warning yell before appearing is "Gak! Mugllglgll! Gak!", so listen for that line to know he is about to arrive.