I found one under Xian Di in Chengdu Jiansan chess game, but I couldn't find the NPC.

The deputy to the National People's Congress at the bottom of Chengdu County Bureau is Xie Xianju, as shown in the following figure:

Task-related:

The crab shell is engraved with a big word "cannon", "thunderbolt is like fire, impatience is like cannon."

Crab cannon and pet star: Samsung

Crab gun category: aquarium

Crab cannon and pet score: 30 points

How to get a crab gun: a world adventure

Task items: chess points, the second half of Xianxian Bureau

Subsequent NPC: Xie Xianju

Crab cannon got a clue: outside the camp of Shu army, the sound of guns was deafening.

Crab gun collection location: outside Chengdu Shu military camp.

Extended data:

Players wander around the camp of the Shu army, paying attention to whether there is anything lost on the ground-Chen Xianju's chess book. If they see it, they will pick it up (using team event monitoring, choose a data containing pets to download and merge).

After picking up Chen Xianju's chess book on the ground, he can turn it into a crab cannon. Because it is a crab, it needs to be domesticated in the player's domestication interface.