FireMode.Rocket.

One pull launches a bolt from the muzzle. Without Double Tap it is a single straight bolt. The bolt ends on impact or range, and the detonation is the rocket blast.

Shop upgrades, all required on Rocket:

• Cluster Warhead — every detonation flings a ring of short-lived mini-rockets that explode in a second beat.
• Double Tap — each pull launches rockets that bloom from the muzzle into a ring around aim, at a raised energy cost.
• Funeral Rites — hits tyrants harder. When a boom wounds a boss or elite, the swarm rushes to defend them.
• Singularity — rockets trail a vacuum corridor that pulls enemies toward the tip. The boom stuns bosses and the wake collapses into the crater. It also makes the rocket more energy-efficient, offsetting Double Tap.

Seeker Burst is not in the shop list. AbilityId marks it delisted. FireRocket still steers the bolt toward the crosshair and cluster-bursts at aim when a level is already on the run. Higher levels turn and fly faster. The top level can detonate on command.