How to type this arrow in math mode?

No tikz...works across math styles.

\documentclass{article}
\usepackage{scalerel,stmaryrd}
\newsavebox\wedgearrowbaseline
\savebox\wedgearrowbaseline{$\scalerel{%
  \ooalign{\kern.05pt/\cr/}\mkern-8.5mu}{\ssearrow}$}
\newcommand{\wedgearrow}{\mathrel{\scalerel*{%
  \usebox{\wedgearrowbaseline}}{X}}} %stmaryrd
\begin{document}
$K\wedgearrow L$

$\scriptstyle K\wedgearrow L$

$\scriptscriptstyle K\wedgearrow L$
\end{document}

Similar to Ahrtaler's answer, the difference being that it also cooperates with subscripts (and all math styles) and becomes bold if one is in bold mode. I recommend this thread for further reading.

\documentclass{article}
\usepackage{tikz}
\usepackage{amsmath}
\makeatletter
\DeclareRobustCommand{\checkbold}[1]{% https://tex.stackexchange.com/a/24635/121799
 \edef\@tempa{\math@version}\edef\@tempb{bold}%
 \ifx\@tempa\@tempb%
  \def#1{1}%
 \else
  \def#1{0}%
 \fi}
\makeatother 
\tikzset{wedge arrow/.style={->,line cap=round,line join=round}}
\newcommand{\wedgearrow}{\checkbold\tmp%
\ensuremath{\mathrel{%
\mathchoice{%
\tikz[baseline=-0.1ex]{\draw[line width={(1+0.33*\tmp)*0.06em},wedge arrow](0,0) -- (60:0.6em) -- ++ (-60:0.6em);}
}{%
\tikz[baseline=-0.1ex]{\draw[line width={(1+0.33*\tmp)*0.06em},wedge arrow](0,0) -- (60:0.6em) -- ++ (-60:0.6em);}
}{%
\tikz[baseline=-0.075ex]{\draw[line width={(1+0.33*\tmp)*0.045em},wedge arrow](0,0) -- (60:0.45em) -- ++(-60:0.45em);}
}{%
\tikz[baseline=-0.06ex]{\draw[line width={(1+0.33*\tmp)*0.035em},wedge arrow](0,0) -- (60:0.35em) -- ++ (-60:0.35em);}
}}}}
\begin{document}
$A\wedgearrow B_{C\wedgearrow D}$ {\Large $A\wedgearrow B_{C\wedgearrow D}$}

\boldmath$A\wedgearrow B_{C\wedgearrow D}$ {\Large $A\wedgearrow B_{C\wedgearrow D}$}
\unboldmath
\end{document}

EDITs:

1. added \mathrel at Eclipse Sun's suggestion.
2. Made the macro detect the font weight, too, so the arrow goes bold in \boldmath or \boldsymbol, just like the standard arrows.
3. Added round line caps and joins, motivated by Joey's comment.

I think you could do something like that:

\documentclass{scrartcl}

\usepackage{tikz}

\newlength{\textsize}

\makeatletter
\setlength{\textsize}{\f@size pt}
\makeatother

\newcommand{\wedgearrow}{%
    \resizebox {!} {\textsize} {
    \begin{tikzpicture}
    \draw[->, line width = 2pt] (0,0) -- (.5,1) -- (1,0);
    \end{tikzpicture}}
}

\begin{document}
    Hi this \wedgearrow is a wedgearrow
\end{document}