—Sharktronic Sand Sub's splash screen
Sharktronic Sand Sub is a Beach zombie introduced in Plants vs. Zombies 3. It appears identical to a Shark Zombie until it is revealed and cannot be damaged until it attacks. Sharktronic Sand Subs can appear in the Beach Trick "Feeding Frenzy", along with Shark Zombies.
Its ability to dig underground is based on the Zombot Sharktronic Sub's ability to dive underwater in the second game.
Its splash screen description is a reference to a famous quote from the 1975 film Jaws: "You're gonna need a bigger boat.". Its description also references how the shark in said film strikes when least expected.
Sharktronic Sand Sub is quite dangerous as it avoids plants until it attacks and has a good amount of armor to withstand damage. Using Buttercup can stun it and give the player a better chance at defeating it; when it has surfaced, Kernel-Pult and Butternut Squash can also stun it. Puff-Shroom can be used to make it surface farther from plants, allowing Sharktronic Sand Sub to be damaged more before it reaches the frontline.
- Unlike his Plants vs. Zombies 2 and Plants vs. Zombies Heroes counterparts, it has a red antenna instead of yellow.