Friend's Yoyo

From Mother - Wiki on Neoseeker

The Friend's Yo-yo is an item that you get by defeating the robot, Mrs. Marshmallow. It is located at the top of Thunder Tower, and only appears once. It is an item for Lucas that raises his attack the most, except for two other weapons. This item is a cameo referring to the Earthbound character Ness, who used Bats and Yo-yos as weapons. The reason it is titled the Friend's Yo-yo is because Porky is the boss here, who was formerly known as Pokey when he was in Earthbound. Mrs. Marshmallow refers to it as "Master P's Friend's Yo-yo", which means Master Porky and Ness.