It's not a very good answer but I don't have enough time to do a new shape and you can find a lot of examples to do a new shape (batman or other shapes) from this answer.
I made manually a cloud and I place the text inside. You can make a macro to draw the cloud and to place the text at the same time.
You can use the node (cloud) to place arrows etc.
What you can do:
- new shape: asym cloud
- or a macro to draw the cloud and to place the text
\documentclass[11pt]{scrartcl}
\usepackage{tikz}
\newcommand{\asymcloud}[2][.1]{%
\begin{scope}[#2]
\pgftransformscale{#1}%
\pgfpathmoveto{\pgfpoint{261 pt}{115 pt}}
\pgfpathcurveto{\pgfqpoint{70 pt}{107 pt}}
{\pgfqpoint{137 pt}{291 pt}}
{\pgfqpoint{260 pt}{273 pt}}
\pgfpathcurveto{\pgfqpoint{78 pt}{382 pt}}
{\pgfqpoint{381 pt}{445 pt}}
{\pgfqpoint{412 pt}{410 pt}}
\pgfpathcurveto{\pgfqpoint{577 pt}{587 pt}}
{\pgfqpoint{698 pt}{488 pt}}
{\pgfqpoint{685 pt}{366 pt}}
\pgfpathcurveto{\pgfqpoint{840 pt}{192 pt}}
{\pgfqpoint{610 pt}{157 pt}}
{\pgfqpoint{610 pt}{157 pt}}
\pgfpathcurveto{\pgfqpoint{531 pt}{39 pt}}
{\pgfqpoint{298 pt}{51 pt}}
{\pgfqpoint{261 pt}{115 pt}}
\pgfusepath{fill,stroke}
\end{scope}}
\begin{document}
\begin{tikzpicture}
\draw (0,0) rectangle (15,10) ;
\node (cloud) at (8,7) {\tikz \asymcloud{fill=gray!20,thick};};
\node at (4,6) {\tikz[cm={-1,0,0,1,(0,0)}]\asymcloud[.15]{fill=gray!20,thick};};
\node at (8,7) {Net};
\end{tikzpicture}
\end{document}
