Even weak and without knowing the full extent of your foe's abilities, you know that you have to stop him; nobody else can, and he's already proven himself dangerous enough to warrant your actions. You saw him trying to escape as you finished his minions, so you fly off in pursuit. You catch up to him quickly; it's almost as if he weren't trying to get away.
"Halt, evil-doer!" you shout upon approach.
"Ah," he says, turning, "I was wondering when you would get here. They slowed you down a lot, didn't they?" You move to strike, hoping to finish the fight quickly, but find yourself unable to move; your ample muscles are meaningless. "Do you like that?" he gloats. "My mental powers will hold you in place until I'm ready to rip you apart." He throws back his head and laugh. It's only then that you can see some sort of device hidden below his cowl.
You have one more ace up your sleeve, and you've just found the right way to use it. You focus your eyes on the outline of whatever he's wearing, supercharging ions in the air between you and your target, igniting them, and incinerating the thing with heat vision. The villain cries out, but there are no words; there's only a long terrified wail as he begins to plummet from the sky.