Limit for Monster Modifiers?

[Xkin]

Hi there,

Since i am a very new munchkin-player, i have a question regarding monster modifiers.
Is there a limit for those? For example, a player throws in a wandering monster, the plutonium dragon. Then the other player uses "mate" on this wandering plutonium dragon... Is this legit? And can the wandering, mated plutonium dragon modified again?

This happend to me, i faced - in addition to the original monster- 2 nasty enhanced plutonium dragons ;)

Sorry for my bad english and thanks in andvance

Xkin