\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) + \left ( y \left ( x \right ) \right ) ^{3}{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -y \left ( x \right ) \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) \sqrt { \left ( y \left ( x \right ) \right ) ^{4}+4\,{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) }=0} \]
Mathematica: cpu = 0.152019 (sec), leaf count = 33 \[ \left \{\left \{y(x)\to \sqrt {2} e^{c_1} \tan \left (2 \sqrt {2} e^{3 c_1} \left (c_2+x\right )\right )\right \}\right \} \]
Maple: cpu = 0.187 (sec), leaf count = 47 \[ \left \{ y \left ( x \right ) ={\frac {1}{{\it \_C1}}\tan \left ( {\it \_C2}\, \left ( {{\it \_C1}}^{-2} \right ) ^{{\frac {3}{2}}}+x \left ( {{ \it \_C1}}^{-2} \right ) ^{{\frac {3}{2}}} \right ) },y \left ( x \right ) ={\frac {1}{{\it \_C1}}\tanh \left ( {\it \_C2}\, \left ( {{ \it \_C1}}^{-2} \right ) ^{{\frac {3}{2}}}+x \left ( {{\it \_C1}}^{-2} \right ) ^{{\frac {3}{2}}} \right ) } \right \} \]