The Seizure Scream is a really powerful Offensive Skill used by Luigi in Achille12345's Skies of CD-I Legends video, when Mario's team was in a near-death state. The usage of this skill turned the tide of the battle, since Iron Knuckle got a seizure attack, allowing Mario & Luigi to fully recover from wounds.
Except for doing moderate damage, the Seizure Scream also gives an opponent a 'Stop' status effect, disabling him from moving and attacking for 2 turns. If Luigi decides to use the attack once more on the enemy after the effect vanishes, the duration of the stun will decrease to 1 turn, making the skill's usage unprofitable, as it costs 30 Focus points. So, basically, it becomes less effective the more it is used.
The scream's sound is Mama Luigi's holler, unassociated with Gay Luigi.