Perhaps each alien should have an ability:
Sectoid: Mind Merge: a special psionic power available to all sectoids, even non-leaders/non-commanders, this boosts an allied sectoid's stats for one turn. However, killing the sectoid using this power will kill the one being affected with merge. Stunning merely removes the bonus.
Floater: Mark Target: a floater can mark one of your units for attack and fellow floaters can fire at him/her with increased accuracy
Snakeman: Poison Breath: a cone-like attack that breathes poison in a direction that spreads out. Snakemen and Chryssalids are immune to poison, soldiers with power armor and flying suit immune as well. Soldiers who are poisoned will lose health for a duration with decreased accuracy stats as well. Soldiers who have been poisoned at least once in a mission will require medical treatment, though poison doesn't leave any fatal wounds. Medikits reduce the duration of the poison and soldiers carrying one have poison status disappear more quickly.
Ethereal: Psi Lance: Ethereal Leaders and Commanders have this psionic ability, which translates into a ranged plasma attack that deals more damage if the soldier fails a psionic test.
Muton: Intimidate: if a muton receives damage, it has a chance to intimidate the soldier who attacked. Intimidation reduces the morale of a soldier and may panic him/her if morale is low enough. Intimidate requires no time units.
