is hemispherical with an inrolled margin, but becomes convex at maturity as the fruit body expands, while in older specimens the margin might be slightly undulating. When young, the pileus is greyish white to silvery-white or buff, but older specimens tend to develop olivaceous, ochraceous or brownish tinges. The surface of the cap is finely tomentose, becoming smooth at maturity and is often slightly viscid in wet weather. The cuticle is tightly attached to the flesh and does not peel. The free to slightly adnate tubes are up to long, pale yellow or greenish yellow and bluing when cut. The pores (tube mouths) are rounded, yellow to orange at first, but soon turning red from the point of their attachment to the stem outwards, eventually becoming entirely purplish red or carmine-red at full maturity and instantly bluing when touched or bruised. The stipe is , extraordinarily , very rarely long, distinctly bulbous (, extraordinarily , very rarely ), and often wider than its length, becoming more ventricose as the fungus expands but remaining bulbous at the base. Its colour is golden-yellow to orange at the apex, becoming increasingly pinkish-red to reddish-orange further down and deep carmine-red to purple-red towards the base. It is decorated in a fine, yellowish to reddish hexagonal net, sometimes confined to the upper half of the stipe. The flesh is thick, spongy and whitish, but may be yellow to straw-coloured in immature specimens and is sometimes reddish at the stem base. It slowly turns a faded blue colour when cut, bluing more intensely around the apex and above the tubes. The smell is weak and pleasantly musky in young fruit bodies, but becomes increasingly putrid in older specimens, reminiscent of carrion. Young specimens have a reportedly pleasant, nutty taste. The spore print is olivaceous green. The spores are fusiform (spindle-shaped) when viewed under a microscope and measure 10–16 × 4.5–7.5 μm. The cap cuticle is composed of interwoven septate hyphae, which are often finely incrusted. Similar species Satan's bolete can be confused with a number of other species: Rubroboletus rhodoxanthus is found predominantly on acidic soil, develops pinkish tinges of the cap, has a more or less cylindrical or clavate stipe with a very dense, well-developed net and lemon-yellow flesh that distinctly stains blue only in the cap when longitudinally sliced. Rubroboletus legaliae is also acidophilous, has pinkish tinges on the cap, flesh that stains more