The Minecraft Wiki is no longer considered as official by Microsoft and therefore several changes are required to be made, including to the wiki's logo. Please read this announcement for more information.
When you gather a soul, you gain a 1% stacking movement speed boost for a short time.
Soul Speed is a common armor enchantment in Minecraft Dungeons that provides a small speed boost when the player gathers souls from mobs. The buff duration is increased with each tier.
Minecraft Dungeons enchantments