#sparkmeld

Necessary references: Worldbuilding: Spark Types, Worldbuilding: Nexuses

Sparkmeld, or more loosely, sparkmerge, is the act of combining two or more sparks into a single life force. In most cases, this is brief link that only lasts a few minutes.

Most Cybertronians consider this a very intimate act. Not only are you sharing your life with someone, but you're also trusting them as completely as you can, baring the one thing that keeps you alive and giving them full access to your frame.

In Earth terms, it's a BIG deal.

Physical Effects

When two sparks combine, the resulting spark, usually, reaches an equilibrium between their power levels. For example, if you combine two sparks, one with a Radiance of 3.4 Lux, the other with 6.2 Lux, like Knockout and Breakdown:

Then while merged, the spark would eventually equalize out to 4.8 Lux, and look like this:

The longer the two are melded, the closer the component sparks would be in color on separation, which temporarily effects their energon output. In Knockout's case, he would burn through more energon until he leveled out, but also get a power boost. In Breakdown's, he would conserve more energon than usual, but be more tired as a result. This lasts for roughly a day, as the sparks slowly return to their original Radiance levels.

While melded, the component sparks don't exist individually. There is one spark, in control of both frames it's linked to, and it exists as one being with a fusion of personalities between the two.

In the case of most sparkmelds, the varying Resonance will force a split after a few minutes of contact, as too much energy is lost to sustain both at once. If the component bots have synchronic Resonance (i.e., their cpnk matches), the meld can last indefinitely.

Synchronic Resonance is what allows combiner teams like Devastator to exist. Rather than fighting itself for resources, the melded spark of the Constructicons behaves as if it were always one entity, adding the components' energies together rather than trying to find equilibrium between them.

Note: Unlike in popular fandom, merging sparks in the MoL continuity does NOT create a perpetual mental/emotional link between bots. There is no permanent change from melding a spark, it exists as an experience.

Sparkmeld and Nexuses

Some (not all) Nexuses are punctuated by a sparkmeld after they've been pledged. In the case of a Nexus of Concord, this is a vital component, albeit it works a bit differently; members of a combiner team will finish their vows off with a test run of their combined form.

Nexus bonds that involve a sparkmeld:

Nexus of Confidence

Nexus of Concord

Nexus of Stability

For these Nexuses, melding is considered fair game to request of your partner after they're pledged. Some bots do it once, then never again, others meld any time they want company; the frequency varies uniquely between each set.

Nexus bonds that do NOT involve a sparkmeld:

Nexus of Apprenticeship

Nexus of Adversity

Nexus of Protection

Since the role of these Nexuses is to teach or protect another bot, rather than understand how they think, melding has no use (and is often impossible, in the case of Metrotitans).

It is EXREMELY uncommon for a bot to want to merge outside of a Nexus, namely because the level of trust it entails often demands a familiarity that would lead to a Nexus in the first place. Still, it's not completely unheard of; especially in wartime, some bots want to know what the experience is like before they die on the battlefield, while others just want someone to share some solace with.

Medical Sparkmeld

In the case of extreme emergency, sometimes a bot might house someone else's spark in their own chamber to keep it alive during an intensive operation.

This is typically a last resort. A frame can't survive very long without its spark powering it, and removing a spark, however temporary, means that the bot will require a long recovery period afterwards. On top of this, the person housing the spark has to have a synchronic Resonance with the patient being operated on, or the chamber will reject the added energy.

When this does happen, the housing donor loses their individual consciousness in favor of the meld (albeit without the memories of the detached frame). Putting it into layman's terms, they become a one-frame combiner.

Note: Putting this into even more understandable terms, they're a Steven-Universe-style fusion. Two components, two minds, but the sum of their parts is a whole new person.

Appendix: Sparkmeld and the Matrix of Leadership

The spark of Optimus Prime, by technicality, can be considered a more permanent meld. Orion Pax's spark took on the Matrix of Leadership's directives and purposes; as such, Optimus isn't Orion, but Orion forms a vital part of who he is.