Orbsium

Orbsium is an orb-type projectile relic effect that repeatedly activates pegs multiple times when it hits them. It appears as a launched orb projectile and is used to create multi-activation effects on individual pegs, making it a high-synergy choice for builds that capitalize on repeated activations rather than single large hits. Orbsium was introduced in the demo release and has received several balance and behavior updates through early access.

Orbsium’s multiple activations cause several notable interactions. Bomb pegs are detonated in a single hit by Orbsium’s multi-activation, so Orbsium is particularly effective in bomb-centric builds that want quick detonations. Relics and effects that count down on activations — for example Mental Mantle and Popping Corn — will decrement once for each activation Orbsium applies to a peg; this also applies to Wand of Skulltimate Power, so combining Orbsium with countdown relics requires care. Effects that grant recurring benefits on activations scale strongly: Glorious SuffeRing’s bonus triggers multiple times with Orbsium, allowing damage scaling to outpace alternatives like Swoltorb. Conversely, any benefit from making pegs Durable (such as from Splatorb or Gift That Keeps Giving) is lost once Orbsium is upgraded at least once, because Orbsium’s upgraded behavior refreshes or overrides durability in its activation sequence.

Practical notes for using Orbsium:

• Use Orbsium in bomb or multi-activation strategies to maximize value; it excels where multiple hits on the same peg are desired.
• Avoid pairing Orbsium with countdown-based relics you do not want rapidly consumed, unless that interaction is intentional for the build.
• Orbsium synergizes very well with relics that grant stacking or per-activation bonuses (for example Glorious SuffeRing), enabling faster power growth than some single-hit orbs.
• Do not rely on durability effects once Orbsium has been upgraded; its upgraded behavior removes the benefit of making pegs Durable.
• Be cautious about taking Matryoshka Shell in standard Orbsium runs unless you have a specific combo, as Matryoshka can cause Orbsium to merely clear the board without productive effects.

Visual and historical notes: the projectile used by Orbsium was originally identical to the Memorb until version v0.6.18, when a unique projectile was added. The orb’s name appears to reference the element osmium, the densest naturally occurring element. Orbsium’s upgrades and hit counts have been adjusted over time (Early Access peg hits were reduced from 3/4/5 to 2/3/4), and later patches adjusted upgrade density, additional hits, and keyword wording to match engine changes.