What kind of transformation is this matrix refering to? 
Given is the 3D transformation $$M_1=\begin{pmatrix} 0 & 1 & 0\\  3 &
0 & 0\\  0 & 0 & 1 \end{pmatrix}$$
What kind of transformation is $M_1$?

I've used several different points \begin{pmatrix}
x\\ 
y\\ 
z
\end{pmatrix}
and did operations with it $$\begin{pmatrix}
x'\\ 
y'\\ 
z'
\end{pmatrix}=\begin{pmatrix} 0 & 1 & 0\\  3 &
0 & 0\\  0 & 0 & 1 \end{pmatrix}\begin{pmatrix}
x\\ 
y\\ 
z
\end{pmatrix}$$
By several test-inputs I know that the solution is always in the form of \begin{pmatrix}
y\\ 
3x\\ 
z
\end{pmatrix}
So basically the $z$ value never changes, but the $x$ value is swapped with the $y$ value and the $x$ value which now is the $y$ value got multiplied by $3$.
I'm really missing the name of the transformation here because it's neither a scaling for me, nor a rotation or a shearing... It's more like a mixture of several transformations (called affine transformation?)? Or there is not really a name for this? It's very confusing I'm sorry if it is :(

$$M_1=\begin{pmatrix} 0 & 1 & 0\\  3 &
0 & 0\\  0 & 0 & 1 \end{pmatrix}$$
$$=\begin{pmatrix} 1 & 0 & 0\\  0 &
3 & 0\\  0 & 0 & 1 \end{pmatrix} 
\begin{pmatrix} 0 & 1 & 0\\  1 &
0 & 0\\  0 & 0 & 1 \end{pmatrix}$$
Looks like a reflection in $y=x$ together with a scaling.
