Metroid
From A complete guide to Super Metroid speedrunning
Metroids are best killed using ice beam and super missiles/missiles, but can also be killed with power bombs. Grouping them together can save ammo.
If a Metroid touches Samus, it will latch on and start doing damage over time. It can be detached with a bomb, but they will latch right back on again. If Samus is moving over the bomb in morph ball form when the bomb goes off, the Metroid will end up a little farther away and give Samus enough time to unmorph and freeze them. Alternatively, Samus can place 3 power bombs to kill the Metroid. These will not detach the Metroid, but the Metroid will stop damaging Samus during the explosions. Exiting and re-entering the room will also detach the Metroid, but this is obviously slow.