Presence of Mind

Effect

Passive: Scoring a takedown against an enemy champion restores 15% of your maximum mana or 15% of your maximum energy after a 1-second delay.

Damaging an enemy champion restores 6; then +0.8*x for 5; then +2*x for 5; then +3.2*x for 5; then +4*x for 2; then +8; then +4 / 6*0.8; then +0.8*0.8*x for 5; then +2*0.8*x for 5; then +3.2*0.8*x for 5; then +4*0.8*x for 2; then +8*0.8; then +4*0.8 mana or 6 energy (8 second cooldown).