Double Mario

Double Mario is a form of Mario introduced in Super Mario 3D World.

In this form, the player gains a doppelgänger of themselves who stays adjacent and copies every movement. The double could be seperated by ramps, ledges, and other obstacles. This form can be used in conjunction with other forms such as Fire Mario and Tanooki Mario. If the player gets another Double Cherry in this form, another copy can be added. The double has no physical difference from the original.

This is also very similar to the Super Mario 128 demo with 128 Marios.