We present a one-dimensional semilinear parabolic equation
$u_t=$u xx$ +x^m |u_x|^p, p> 0, m\geq 0$, for
which the spatial derivative of solutions becomes unbounded in finite time while the solutions themselves
remain bounded. We show that the spatial derivative of solutions is globally bounded in the case
$p\leq m+2$ while blowup occurs at the boundary when $p>m+2$. Blowup rate is also found for some
range of $p$.