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Abstract One of the simplest (1, 0) supersymmetric theories in six dimensions lives on the world volume of one M5 brane at a D type singularity ℂ2 /D k . The low energy theory is given by an SQCD theory with Sp(k − 4) gauge group, a precise number of 2k flavors which is anomaly free, and a scale which is set by the inverse gauge coupling. The Higgs branch at finite coupling ℋf $$ {\mathrm{\mathscr{H}}}_f $$ is a closure of a nilpotent orbit of D 2k and develops many more flat directions as the inverse gauge coupling is set to zero (violating a standard lore that wrongly claims the Higgs branch remains classical). The quaternionic dimension grows by 29 for any k and the Higgs branch stops being a closure of a nilpotent orbit for k > 4, with an exception of k = 4 where it becomes minE8¯ $$ \overline{{ \min}_{E_8}} $$, the closure of the minimal nilpotent orbit of E 8, thus having a rare phenomenon of flavor symmetry enhancement in six dimensions. Geometrically, the natural inclusion of ℋf⊂ℋ∞ $$ {\mathrm{\mathscr{H}}}_f\subset {\mathrm{\mathscr{H}}}_{\infty } $$ fits into the Brieskorn Slodowy theory of transverse slices, and the transverse slice is computed to be minE8¯ $$ \overline{{ \min}_{E_8}} $$ for any k > 3. This is identified with the well known small E 8 instanton transition where 1 tensor multiplet is traded with 29 hypermultiplets, thus giving a physical interpretation to the geometric theory. By the analogy with the classical case, we call this the Kraft Procesi transition.