Many new idiotic and non-idiotic protectors are announcing themselves as "anti-dumping" ones. It may include:
1) Detecting given process dumper (e.g. ProcDump) in memory and deleteing it, using, e.g. TerminateProcess
2) Possible hiding from process dumper by hooking several API functions (for example, the ones that belong to PSAPI or even native ones like NtQuery*)
3) Simple erasing or filling with garbage the PE Header in memory (not always possible, but...) - teLock does this encreasing NumberOfSection to 2xx that causes dumped process to fail during next launch.
4) ???

Who can continue and make this list wider... I would highly appretiate any examples with assembly code. May be anyone knows anything about VirtualProtect or sth like this...