As part of the 25th anniversary of Nickelodeon’s “SpongeBob SquarePants” franchise, the new game “SpongeBob Simulator” will be available on Jan. 26 to Roblox’s 70 million-plus daily users.

Technically an “experience” within the game-creation platform Roblox, it smashed its own record for concurrent users by reeling in 16.4 million active players on Saturday. It is a genuinely ...