The alien mower is a "secret" mower hidden in a secret shop in Mow My lawn. This is the last of the "buyable" mower type mowing devices that do not come in gamepasses. This is the cheapest of the alien tech and the worst compared to the other 2 but good compared to the common stuff around its cost.
It costs 500 million trimmings in the secret shop.
The three secret alien items were all designed (but not coded) by Dannyha, a fan of Mow My Lawn.