Ultimate Mortal Kombat 3 Wave Net was a rare network version of the game. It was only tested in the Chicago and San Francisco areas that used a dedicated T1 line, connected directly to Midway's Chicago headquarters; many people outside the test area were not aware of its existence during its release. One store kept the T1 line installed after the test concluded, but eventually removed the Wave Net game in favor of a Golden Tee game that uses a dial-up connection. It is highly unlikely that any Wave Net test games were ever released to the public after the infrastructure was dismantled, and so there are no known dumps of the ROMs used by the games designed for it.
One of the reasons this version was not widely adopted was the rarity and cost of T1 lines at the time. The game was released before alternative broadband access was available. At the time, a T1 was the only guaranteed way to get broadband into an arcade, but the game didn't utilize the full bandwidth of the T1. Midway subsidized the cost of the line during the tests to make it more attractive to the arcade owners.