After my opinion: It is possible:
Godmod:
-plrsetimmune=1 make the player immune from damge
-plrsetimmune=0 make the player not immune from damage
Freezing:
also possible with a code like this
:plrfacing=10,keypressed=33 1:animate=1,etimerstart,state=100
:state=100,etimergreater=3000:state=0
Not knowing if this is so possible, but this is a hint how to
shrinking:
:keypressed=34 1:setvar=$CPY -10,entityaccmult=50
flying:
after my opinion, this is not possible without sourcecode modification. sry
Hope this help you
Corno_1