Basic Action Super Heroes!

Characters with Bouncing are Immune to damage from Slams (or falls).

So then, if a bouncing hero tries to Slam Attack an opponent and fails the attack contest (that normally causes him damage for failing), would he TAKE this damage or would he be IMMUNE to his own Slam damage?

He's immune. Yes, Slam is a VERY EFFECTIVE attack for people with Bouncing; this is intentional.