Suppose your opponent casts pyroblast (mode destroy target blue permenants) targeting your pestermite. Can you use spellskite to itself / misdirection to redirect to another permenant?
2) what about the same senario, but your opponent chose the mode "counter target spell) can you misdirect to another permenant or redirect it to spellskite
I'm actively maintaining a comprehensive article to help explain to new cube players how some complex vintage level cards work in a cube environment. Vintage Cube Cards Explained
You can't redirect a spell to a target that is not valid, according to the wording for that spell's target.
However, Pyroblast second mode does not say "destroy target blue permanent". It says "destroy target permanent if it is blue". The targeting restriction is just "permanent", not "blue permanent", so you can have Spellskite redirect Pyroblast to itself, or use Misdirection to have it target any one permanent. And if that new target isn't blue, it won't be destroyed.
Now, the similar spell Red Elemental Blast does say "destroy target blue permanent", so the new target must still be a blue permanent. Spellskite doesn't work with it.
And if Pyroblast (or REB) was cast with its first mode (targeting a spell), it can't be redirected to a permanent at all.
I'm actively maintaining a comprehensive article to help explain to new cube players how some complex vintage level cards work in a cube environment. Vintage Cube Cards Explained
2) what about the same senario, but your opponent chose the mode "counter target spell) can you misdirect to another permenant or redirect it to spellskite
Vintage Cube Cards Explained
Here are some other articles I've written about fine tuning your cube:
1. Minimum Archetype Support
2. Improving Green Archetypes
3. Improving White Archetypes
4. Matchup Analysis
5. Cube Combos (Work in Progress)
Draft my Cube - https://cubecobra.com/cube/overview/d8i
However, Pyroblast second mode does not say "destroy target blue permanent". It says "destroy target permanent if it is blue". The targeting restriction is just "permanent", not "blue permanent", so you can have Spellskite redirect Pyroblast to itself, or use Misdirection to have it target any one permanent. And if that new target isn't blue, it won't be destroyed.
Now, the similar spell Red Elemental Blast does say "destroy target blue permanent", so the new target must still be a blue permanent. Spellskite doesn't work with it.
And if Pyroblast (or REB) was cast with its first mode (targeting a spell), it can't be redirected to a permanent at all.
Vintage Cube Cards Explained
Here are some other articles I've written about fine tuning your cube:
1. Minimum Archetype Support
2. Improving Green Archetypes
3. Improving White Archetypes
4. Matchup Analysis
5. Cube Combos (Work in Progress)
Draft my Cube - https://cubecobra.com/cube/overview/d8i