The big boss of Solutional Haunt (Alloyed Collective): it cannot move sideways and barely takes damage.

| In-game title | The Alloyed Collective |
| Type | Special boss |
| Expansion | Alloyed Collective |
| Health | 6069 (+1821 per level) |
| Base damage | 15 (+3 per level) |
| Armour | 1000 |
| Where it spawns | In Solutional Haunt, through the virtual portal. |
Fires spheres that slowly chase you and explode.
How to dodge it: Break them before they reach you.
Rings of blue (and later red) walls that move outwards.
How to dodge it: You have to jump them or change floors: use the ramps, ziprails or energy pipes.
Charges and fires a huge laser that tracks you; the arena fills with light.
How to dodge it: Hide behind a real wall (the vents do not block it) or ride a ziprail.
A grid of lasers that rises from the floor or drops from the ceiling, with big gaps.
How to dodge it: Go through the gaps.
In Solutional Haunt, through the virtual portal.
6069 base health, plus 1821 per enemy level. Armour: 1000.
Sources: the Risk of Rain 2 wiki (each boss page and Module:Enemies/Data, read on 31 October 2026) and the game's own text. The explanations are our own. Icons: Risk of Rain 2 (Hopoo Games / Gearbox).