Mr. Fungi is a weapon in Rift Apart. It is a deployed automatic attack drone in the form of a fungi-like companion that spits poison at Ratchet and Rivet's enemies. Multiple Mr. Fungi can be deployed at once, and will send insults at enemies while firing at them and promising to send "fun" their way.
Mr. Fungi can be purchased from Ms. Zurkon in Nefarious City, Corson V for 3,000 bolts. At level 5, it upgrades to Ms. Fungal. In challenge mode, the Omega Ms. Fungal can be purchased for 50,000 bolts.
A deployed Mr. Fungi will spit poison blasts at enemies nearby, protecting Ratchet or Rivet. Mr. Fungi has a moderate rate of fire and a short-to-medium range, but can be effective in providing complementary damage. Particularly, multiple Mr. Fungi can be deployed to help combat an overwhelming mob of enemies.
The raritanium upgrades for Mr. Fungi generally improve Mr. Fungi's existing capabilities, while not drastically changing the weapon. The Max Fungis upgrade is especially useful, as allowing more to be deployed at once makes the weapon much more valuable.
Once fully upgraded with XP, Mr. Fungi becomes Ms. Fungal. Throughout the game, it remains a useful tool at Ratchet or Rivet's disposal, though more options become available later on. The Glove of Doom also grants aid that supplements Ratchet or Rivet's damage and can distract enemies, but while it is stronger in this regard, the Glove of Doom's Agents are only effective against grounded enemies due to being melee-only, meaning Ms. Fungal remains useful.