Giant Antlion

From Mother - Wiki on Neoseeker

The Giant Antlions are enemies in the Death Desert in Mother 3. They are fairly strong, but you can always use a can of Bug Spray that is found in the desert. This is their weakness.

Appearance

The Giant Antlions look like ants and cockroaches mixed together than thrown into quicksand. On the World Map, they will only appear as a pool of sand. When you go up to this sand however, they will attack you. They have high defense and attack, so they are like a mini-boss if Salsa is underleveled. Then, use a can of Bug Spray, and they will be dead automatically. They don't give much EXP, but they are good if you are grinding.

One of the Giant Antlions captures a Save Frog. Defeating the Antlion saves the frog, so you can save your file.