Grapple: Engaged in wrestling or some other form of hand-to-hand struggle
with one or more attackers. A grappled character cannot move or take
any action more complicated than making a barehanded attack, using a
small weapon or a power, or attempting to break free from the grapple.
In addition, grappled characters lose any dodge bonus against opponents
they aren't grappling.
Pinned: Held immobile (but not helpless) in a grapple. Pinned characters
lose their dodge bonus and suffer a -4 penalty to Defense.
The above means a character by default can use mental action powers, things that require a move action or less (many of the alternate form, shapeshift, elongation, or similar applies in this case), unarmed attacks, strikes like claws or powers that are like strikes.
If you do though, that also means you forgo your use of the grapple that round to escape.
Steve (Guru of MnM) ruled using Teleport would be allowed, with a DC 20 concentration check. Similarly, I'd say anything that made sense to escape a grapple only, like flight as a sudden kick off of speed, or even superspeed to vibrate out of the grip, can be used with a DC 20 concen check to escape in substitute of the grapple check (so takes a standard action). Or without it… a straight dc 20 check with the power ranks vs it.
PL*3 is the max cap of grapple modifier, and PCs may use extra effort (causing themselves fatigue) to gain an alternate power that may help them escape. This bonus will make them equal to the other person's grapple modifier at most though, basically making it a 50/50 chance to break out. Fatigue maybe negated by the Luck feat for grapples only, not for any other uses.
Grapples are NOT effected by the feats accurate attack, all out attack, or similar temporary PL shift feats. It is effected by Growth, shrinking, etc, but the attack modifiers again do not modify the grapple checks (a huge character doesn't suddenly get a penalty to grapple), as ruled by Steve.
