Phase 1: Shadow mutant (the Eyes Are a bit Lighter blue, or cloud blue it's Rare) Phase 2: Red eye Shadow mutant (it's a Classic Shadow mutant with Red eye it's a bit more Strong then a Normal Form shadow mutant)
Concept for more hardmode Phase 3 : Blood rage Shadow mutant (Shadow mutant with red eyes and blood from his footsteps,Dark blooded color and more stronger than normal and red eye form, and common mutants spawns with full armor)