Target Blast Stadium
From SmashWiki, the Super Smash Bros. wiki
The Target Blast Stadium is a Special Stage similar to the Home Run Contest stadium. It is a playable stage as part of Target Blast in Super Smash Bros. 4. It has a platform where the bomb and the fighter stands on and a set of Targets and blocks at the end.
The stadium itself has three different variants, each differing in size. In addition, there is no legitimate way to play any of the three stages outside of the Target Blast mode. Normally, the player can only access the platform where they and the bomb start.