Twinkle Popper

This one appears only during the Lunar Events, in the ground around the Stardust Pillar. Nothing summons it directly and it never spawns in an ordinary world. Kill the Lunatic Cultist, the pillars drop out of the sky, and the stardust one keeps producing these until the pillar itself falls.

Left to itself it barely moves, plodding along the ground at a crawl. The danger starts the instant it can see you. It plants itself and starts coughing up Twinkles at a steady clip, and it keeps doing that for as long as you stay in view and in range. The one gap in the pattern is that it cannot produce anything while it is airborne, so a popper knocked off a ledge stops working until it lands.

Twinkles move several times faster than the thing that made them and run straight at you. Get one underneath your feet and it bursts, throwing sparkles upward into you. Ignore it and it detonates on a short timer anyway. Kill it first and the explosion never happens, which makes ground-clearing weapons worth more here than single target damage.

Two approaches work. Break line of sight, because a wall or a rise in the terrain shuts production down completely, or focus the popper and let the loose Twinkles expire. Fighting from a platform above the ground helps, but the sparkles travel upward, so height on its own is not safety.