The Alpha Splinter is your first mini-boss encounter in the Temple Grounds. It's a larger, more aggressive version of the standard Splinter. Its primary attack is a charge, attempting to ram Samus. It can also spit projectiles. The arena is relatively small, so focus on dodging its charges.
Strategy: The Alpha Splinter's weak point is its glowing red core, which is exposed when it charges or after it attacks. Lock onto it with your Power Beam and fire charged shots or missiles. After taking some damage, it will retreat into the ground and summon smaller Splinters. Quickly dispatch these with your Power Beam, then prepare for the Alpha Splinter to re-emerge and repeat the process. Keep moving and prioritize hitting its core when exposed. Reward: Missile Expansion.