This infested friend cannot be killed by god or man, thanks to the combination of Mecha Pulse, Link Armor, and Synth Fiber.
Link Armor is based on the current armor of your Warframe, which can be absolutely massive with Mecha Pulse active, and Synth Fiber is multiplicative after other armor buffs - or in other words, it takes the armor gained from Link Armor and doubles it.
With Iatric Mycelium and Medi-Pet Kit providing regeneration and Volatile Parasite taking some aggro, this Predasite can be next to impossible to kill.
Paired Warframe build(s): Lavos, Mecha-brand Master Transmuter Nidus Prime - Steel Path | Mecha Insatiability | Stop Using Adaptation You Coward
Other options:
- Replace Medi-Pet Kit with Synth Deconstruct if the kubrow isn't going into bleedout often, for additional health orbs for you and [Synth Fiber].