How can I beat that challenger? A decent strategy would be appreciated.

Mutant Scientist is one of those challengers who block a lot. Her lab coat blocks 100 physical, dark, light, water, wind, earth and her blessing blocks 100 ice. She does not block fire or magma. Use this to your advantage.

The best way to beat Mutant Scientist is to chain freeze. Freeze her the first turn, use those Scientist specs you won from Mad Scientist, while blocking (everything is best) with something such as a Rainbow Vortex or Shinwas Temple Shard. Hopefully she won't freeze you at the same time. If you can keep her frozen you may have a good chance. Otherwise she's pretty much a wrecking ball that will chain freeze you if you let her.

It might be a good time to bump up Telefasts' intel and equip as many freezing scrolls as you can.
Have you looked up her stats and icons she deals on the Comprehensive Guide to Battle Opponents (v2)?

and I was just about to make a post thank you I'm trying to get my 5 to 10 wins
time to change my weapons and scrolls it seems.

You Won! You have defeated Mutant Scientist 5 times!

You won a(n) Impossible token to use in the battle shop!

You earned 9842 sP for beating Mutant Scientist!

Princess earned 3425 EXP Points!

think Ill remove my void scroll and add more shreiks i used a lot of potions too