IM-01 is special mine ammunition that was available only during the Parasite Tide event, but now you can buy it in shop for 54 Uridium per one mine. It does the same damage as an ACM-1 mine but also applies plague debuff to it's target. The effect can be cured using an ANTIZ-1 CPU .

Also, IM-01 looks like the pirate mines used in the 5-x maps as an offensive trap.