Space Station 13 - Modules - Types

code/datums/status_effects/status_effect.dm

/datum/status_effect/groupedStatus effect from multiple sources, when all sources are removed, so is the effect Adds itself to sources and destroys itself if one exists already, there are never multiple
/datum/status_effect/transientA status effect that works off a (possibly decimal) counter before expiring, rather than a specified world.time. This allows for a more precise tweaking of status durations at runtime (e.g. paralysis).